Materials Research Express
ACCEPTED MANUSCRIPT
Structural, transport and collosal dielectric properties of A-site substituted La2NiO4 To cite this article before publication: Mohd Saleem Malla et al 2018 Mater. Res. Express in press https://doi.org/10.1088/2053-1591/aaecf7
Manuscript version: Accepted Manuscript Accepted Manuscript is “the version of the article accepted for publication including all changes made as a result of the peer review process, and which may also include the addition to the article by IOP Publishing of a header, an article ID, a cover sheet and/or an ‘Accepted Manuscript’ watermark, but excluding any other editing, typesetting or other changes made by IOP Publishing and/or its licensors” This Accepted Manuscript is © 2018 IOP Publishing Ltd.
During the embargo period (the 12 month period from the publication of the Version of Record of this article), the Accepted Manuscript is fully protected by copyright and cannot be reused or reposted elsewhere. As the Version of Record of this article is going to be / has been published on a subscription basis, this Accepted Manuscript is available for reuse under a CC BY-NC-ND 3.0 licence after the 12 month embargo period. After the embargo period, everyone is permitted to use copy and redistribute this article for non-commercial purposes only, provided that they adhere to all the terms of the licence https://creativecommons.org/licences/by-nc-nd/3.0 Although reasonable endeavours have been taken to obtain all necessary permissions from third parties to include their copyrighted content within this article, their full citation and copyright line may not be present in this Accepted Manuscript version. Before using any content from this article, please refer to the Version of Record on IOPscience once published for full citation and copyright details, as permissions will likely be required. All third party content is fully copyright protected, unless specifically stated otherwise in the figure caption in the Version of Record. View the article online for updates and enhancements.
This content was downloaded from IP address 134.226.14.55 on 01/11/2018 at 02:40
Page 1 of 25
Structural, transport and collosal dielectric properties of A-site
cri pt
substituted La2NiO4
M. Saleem, Diksha, A. Mishra and D. Varshney
Materials Science Laboratory, School of Physics, Vigyan Bhawan, Devi Ahilya University, Khandwa Road Campus, Indore 452001, India.
us
Abstract: A-site substituted nickelates of the type La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) prepared via solid state reaction route are reported. X-ray diffraction (XRD) data analysis confirms the type of phase and structure of synthesized samples. All the samples were found to have
an
crystallized into the tetragonal structure (I4/mmm). The XRD results were further verified using Rietveld refinement technique and tetragonal structure with space group (I4/mmm) was confirmed for all the prepared samples under investigation. The single phased tetragonal lattice structure formation was also confirmed from Raman scattering spectroscopy via stretching modes of vibration
dM
displayed by the prepared nickelates around 440 cm-1 and 220 cm-1. The elemental composition was verified using EDAX technique while FESEM images revealed the porous nature and heavy agglomeration. The dielectric studies confirmed the collosal dielectric constant with lowered loss values in the frequency range of 105-106 Hz with retained dielectric constant in the range of 103-104 at 106. The low temperature four-probe dc resistivity measurement revealed the samples are
pte
semiconducting in nature.
ce
Keywords: Nickelates; Structure; Retvield refinement; dielectric properties. *Authors
correspondence address:
[email protected]
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
1
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
1
Introduction
Oxides with colossal dielectric constant (CDC), inherit enormous scientific and technological value as they are considered to be the potent members to find their use in the advanced electrical energy
cri pt
storage i.e. charge storage devices [1]. Among these oxides, the K2NiF4-type exhibit interesting electrical and magnetic properties due to which they have attracted the researchers for their use in solid oxide fuel cells as electrode materials (SOFCs), oxygen separation membranes, high-Tc superconductors, substrates for thin films of high-Tc superconductors and lasers [2-5].
La2NiO4 systems have been identified as promising cathode materials that have capability to
replace the high temperature electrode materials in the lanthanum manganite perovskite family.
us
Despite their coefficient of thermal expansion (CTE) comparable to electrolytes, they exhibit a mixed ionic and electronic conduction character. However, low electronic conductivity of La2NiO4 is still an issue that demands effective address [1-6]. La2NiO4, a perovskite-derived from K2NiF4-
an
type mixed ionic–electronic conductor, shows high oxygen transport across a large temperature range and is an important candidate in SOFC cathode materials [7]. Structurally, La2NiO4+δ is a member of the Ruddlesden-Popper family with tetragonal crystal structure (space group I4/mmm) and consists of alternating LaNiO3 perovskite-like layers and possess "La2O2" rocksalt-like layers in
dM
an arrangement of offset ABA'B'. In this type of structure, the equatorial oxygen sites lie within the perovskite plane while as axial sites bridge the layers. Incorporation of interstitial oxygen within the rocksalt layers is remarkably facile, and affords a considerable range of oxygen hyper stoichiometry (δ) for SOFC applications [8, 9].
In recent years, so many materials of K2NiF4 type have been prepared and in the thirst for new giant dielectric constant materials, the synthesis of modified K2NiF4+δ structure materials was
pte
essential [10-12]. Later some modified K2NiF4 materials were prepared which display excellent dielectric properties. In the same manner, the La2NiF4 materials were modified by doping, doping concentrations, type of doping, calcination and sintering temperatures, preparation procedures etc. which all effected the nature of the La2NiO4 based materials [13-15]. Since La2NiO4+δ is a member
ce
of K2NiF4 family, it is therefore necessary to investigate the dielectric properties of modified La2NiO4 system.
Alkaline earth metal doped La2NiO4+δ has been studied [16] and were found to exhibit
colossal dielectric constant however, the basic physics underlying this CDC is still a mystery. Some researchers have related this conduct of CDC material to “charge glassiness” or polaron hopping
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
while others have discussed it in terms of the Maxwell–Wagner relaxation induced by 2
Page 2 of 25
Page 3 of 25
inhomogeneous charge distribution [13-17]. This CDC character of K2NiF4 type materials has been explained by means of [18] establishing the relationship among structural parameters, parameters related to polar-phonon modes, and dielectric nature. These materials display high dielectric constant
cri pt
well into the gigahertz range and many a times suffer from large frequency dispersion. These
properties in addition with low losses into the gigahertz range confirmed them to be the potent materials for capacitor applications [10-18].
As these materials seem to be promising materials, we have tried to modify this collosal
behaviour in the sense of doping parent La2NiO4 at A-site. We doped La2NiO4 by low concentration of Y and Ba to prevent any structural transition and explore the dielectric behaviour. We succeeded in the maintenance of higher dielectric constant with minimized loss. This article is focussed on the
us
structural and dielectric properties in the light of dopants and their nature in addition to the effect of firing temperatures. From our current piece of work, we expect a little contribution in the said area
CDC.
2
Experimental Details:
an
by opening the window to go for new way doping with new featured properties in addition to the
The polycrystalline samples La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) were synthesized
dM
by the solid-state-reaction method. The starting materials were highly pure (>99.9%) powders of La2O3, NiO, Y2O3 and BaCO3. All the starting materials were used without pre-heating except La2O3 which was pre-heated at 600 oC for 6h to remove moisture. The oxides were weighed in stoichiometric ratios and mixed in an agate mortar. The mixture was calcined at 1050°C and 1150°C for 20h with intermediate grinding of 5h each. The polyvinlyalcohol was used as a binder for the so obtained powders which were pressed into pellets of the diameter of 10mm at a pressure of 7
pte
tonnes/inch under hydraulic press and sintered at 1300 0C for 24h. The pellets were cut into rectangular bars of length of 5mm and width of 1.1mm for four probe dc resistivity measurements. X-ray diffraction measurements of samples were carried out with CuKα1 (1.5406Å) radiation using Bruker D8 Advance X-ray diffractometer over the angular range 2θ (10°-90°) generating X-
ce
ray by 40kV and 40mA power settings. Rietveld refinement was done by Software Fullprof. Morphology studies have been carried using field emission scanning electron microscope (FESEM) instrument of mode SUPRA 55 having resolution of 1.4 nm at 1 kV without beam deceleration, magnification power range of x12 – 900000kVand acceleration voltage of 0.1 to 30kV and energy dispersive x-ray analysis (EDAX) were performed by energy-dispersive spectrometer, model INCA
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
Oxford. Jobin Yuon Horiba LABRAM-HB visible (system HR800) spectrometer, with argon 3
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
(488nm) as excitation source equipped with a peltir cooled charged coupled device detector was used for Raman spectroscopy in the range of 100 to 1200 cm-1. Fourier Transformation Infrared Spectroscopy (FTIR) was done by Perkin Elmer FT-IR/FIR spectroscopy in the range of 400 to 4000
cri pt
cm-1. The temperature dependence of resistivity for the samples La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) has been examined using conventional dc four probe method in the temperature range 35-300 K.
3
Results and Discussions
3.1
Structural Analysis
The polycrystalline samples La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) ortho-nickelates
us
were prepared via conventional solid state reaction route [19, 20]. The phase type and crystal structure was examined through the x-ray diffraction technique. The data so obtained has been
plotted and displayed in the Figure1. The analysis of the XRD spectra revealed that all the samples
an
crystallized into the tetragonal structure with space group I4/mmm and all the peaks were in accordance with the JCPDS-00-011-0557 card. The phase has been retained for all the A-site doped La2NiO4 samples which is indicative of the uniform distribution of the dopants at their respective sites. The homogeneous dispersion is possible for the comparative ionic radii of the dopants and the
dM
respective parent sites i.e. [La3+ =1.061Å, Y3+=0.893Å, Ba2+=1.34Å and Ni2+=0.69 Å [21, 22]. The increase in the calculated lattice parameters of the doped samples compared to the parent sample is attribute to the higher ionic radii of the dopants [19- 22]. The intense characteristic peaks of the as prepared samples revealed the crystalline nature and narrowness of the FWHM is indicative of the larger crystallite size which was calculated using Scherer’s formula, t = kλ / βcosθ, where‘t’ is crystallite size, k = 0.9 called the shape factor, λ = 1.5406 Å, wavelength of the X-rays used, ‘β’ is
pte
FWHM and ‘θ’ is diffraction angle. The average crystallite size calculated was found 126.85 nm, 76.64 nm and 118.04 nm, for La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) respectively. The average crystallite size was further verified from the Retvield refined data and the values found were 129.05 nm, 79.11 nm and 113.21 nm for parent, Y3+ and Y3+/Ba2+ doped La2NiO4. The results are
ce
in close agreement with those obtained from the Scherer’s formula. The results achieved after the analysis of the X-ray spectra of the as prepared samples were further confirmed by fitting the data with the help of Rietveld refinement process using FullProf software [23]. The Rietveld refined data has been plotted and displayed in the Figure 2. The results obtained
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
from the refinement confirmed the structure, type of phase, space group and various other parameters. The details of the refinements are given in the Table 1. The crystal structure of the 4
Page 4 of 25
Page 5 of 25
pristine La2NiO4 sample under study has been depicted in Figure 3. In the Figure 3, it is clear that
3.2
cri pt
both Y3+ and Ba2+ have occupied the La-site while the octahedral Ni-site (NiO6) is unaffected.
Raman Scattering Studies
As a result of dark blackish colour of the samples, the data collection for Raman spectra of materials
was a difficult task by virtue of very strong light absorption. The photon energy is directly converted
into heat that leads to structural transformations [24]. Raman spectra of samples at room temperature in the energy region between 100 and 1200 cm -1 is shown in Figure 4 within the limits of which two
us
peaks have been observed.
In tetragonal I4/mmm (D174h) symmetry 14 optic modes are expected assigned as 2Eg+2A1g+5Eu+4A2u+B2u. Out of these modes, 4 phonon modes namely 2Eg+2A1g are Raman active, 7 modes viz. 4Eu+3A2u are infrared active. Since the symmetry depends on the oxygen
an
stoichiometry, we can modify it by sintering and laser heating [25]. For (La1-xSrx)2NiO4, the two Raman modes were observed at 450 cm-1 and 240 cm-1 assigned to the Ni-O stretching (A1g). However, in the present piece of work, these modes of vibration have been observed at ≈ 440 cm-1
dM
and ≈ 220 cm-1 confirming the tetragonal structure of the prepared samples. The slight shift may be due to doping concentration or may be due to preparation procedure and thermal effects [25, 26].
3.3
Compositional and Morphological Studies
The doped nickelates represented by the general chemical formula La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) have been verified for the composition using the energy dispersive X-ray analysis (EDAX) technique and the energy spectra obtained is displayed in the Figure 5. The close
pte
examination of these spectra reveals that within the limit of experimentation, there is no trace of foreign element in the samples under observation and all the comprising elements are present in the whole series. The composition of the compounds in the sense of presence of the elements and their concentration has been verified and the energy reflections are as per their concentration in the
ce
samples.
The micro-structure and hence morphology of the as prepared samples has been investigated
exploiting the most effective technique viz. field emission scanning electron microscopy (FESEM). The micrographs for the samples namely La2NiO4 and La1.95Y0.05NiO4 in the scale of 5µm are
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
displayed in the Figure 6. The careful observation of the micrographs of the samples display the 5
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
effect of high temperature sintering i.e. the average particle size has grown tremendously as a result of easy diffusion process facilitated by the extreme temperature treatment. It is clear from the micrograph of the samples of La2NiO4 that the grain growth trend is spherical and all the particles
cri pt
are well separated without any definite grain boundary. La1.95Y0.05NiO4 reveals the growth of the grains in the irregular shapes and displays the grain boundaries to some extent in addition to the heavy growth in the average particle size. All the prepared samples reveal agglomeration process
has taken place while sample preparation. Also all the synthesized samples displayed porous nature
which heavily influence the properties of the materials [27-30]. For the calculation of the average particle size, we used ImagJ software and the average size for La2NiO4 and La1.95Y0.05NiO4 were
us
found to be 1.497µm and 1.327µm respectively. This huge growth in the average particle size are
believed to be the result of high temperature sintering which leads easy mass transport phenomenon.
3.4
Fourier Transform Infrared Spectra Analysis
an
The FTIR spectra of the La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) have been displayed in the Figure 7 and data analysis revealed that in the parent and doped orthonickelate La2NiO4, two IR bands were observed corresponding at ≈648 cm-1 and ≈500 cm-1. These results confirm that all the prepared sample have K2NiF4 type structure. The band at≈ 648 cm-1 is attributed to stretching of Ni-
dM
O bond of NiO6 octahedron in the La2NiO4 based material that corresponds to E2u vibrational modes [31, 32]. The other strong band visible at ≈500 cm-1 is assigned to stretching vibrational mode of LaO-Ni bond and has been assigned to A2u vibration mode [33, 34]. In all these samples there is hardly any notable shift in the absorption band in the vicinity of ≈ 648 cm-1 and ≈ 500 cm-1 with dopant on A-site of the La2NiO4 which clearly indicates that the dopants are uniformly distributed corresponding to their sites of substitution. However, the intensity of the
pte
bands have increased slightly which may be attribute to the extent of porosity in the sample. Since there is slight variation in the lattice parameters in the Ba and Y substituted La2NiO4 compared to parent La2NiO4 and the structure is maintained over large doping concentration of x ≈ 0.5 in La2NiO4 and hence its antiferromagnetic insulator nature. Therefore, slight shift observed in IR peaks indicate
ce
stability of structure and nature of the as prepared samples [22, 35].
3.5
Four Probe dc Resistivity Studies
The temperature dependence of resistivity, ρ(T), of La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) ortho-nickelates was measured in the range of temperature from ≈30 to 300 K using
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
conventional four-probe technique with and without magnetic field displayed in the Figure 8. In the 6
Page 6 of 25
Page 7 of 25
absence of magnetic field, the extent of resistivity increases rapidly in the exponent shape as compared to that of presence of magnetic field. The behaviour displayed by the as prepared samples reveal the semiconducting nature in the whole range of temperature. In all the cases, we have
cri pt
observed that the resistivity in the presence of magnetic field is diminished to more than its half. This character may be attributed to the suppression of the scattering from lattice vibrations due to low temperature and the applied field as low temperature helps in the arrest of lattice vibrations and the magnetic field aligns the charge carriers. The conduction process for the semiconductors and insulators including the thermal activation can be successfully explained by the small polaron hopping, the variable range hopping models and thermal activation model also known as the bandgap (BG) model [34 -38].
us
The resistivity behaviour is in accordance with the physical phenomena as the parent
La2NiO4 is antiferromagnetic insulator, it is certain that lower temperature will arrest lattice vibration responsible for any electron movement and increase in temperature will enhance lattice vibration
an
and hence the electron movement resulting in the decrease of resistivity [16]. Since the prepared samples are insulating in nature, upto to certain extent of temperature the phonon motion is awakened and later the resistivity will remain constant as is shown by the samples. Close observation
dM
of the resistivity vs temperature plots for the synthesized samples reveals the increase in resistivity. This character is attributed to the increase in trap centers created upon doping. One more factor as revealed from the calculated parameters is the concept of lattice constants that represent the dimensions of the unit cell. If the doping leads in the increase of the lattice constant, volume of the cell increases and hence the number of charges per unit volume decreases which in turn increases resistivity. Based on this dielectric constant increases with increase in volume.
Dielectric Studies
pte
3.6
The aim of the current work is represented by the frequency-dependent dielectric constant confirming the collosal dielectric nature of the samples. The dielectric measurement has been given in the range of 105 Hz to 106 Hz. As is clear from the plots that the dielectric constant retains its higher value even after the frequency value of 1 MHz. The parent material La2NiO4 possesses a
ce
dielectric constant of 1.1x107 at a frequency of more than 105 Hz and retains a value of 5.5x104 at 1 MHz and is displayed as the inset of the Figure 9. It has been claimed that a charge-ordered nickelates retain their colossal magnitude larger than 104 into the GHz range and the reason for enhanced dielectric constant is possibly charge-order due to inhomogeneous charge distribution. Also the bond
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
length variation at A-site may lead to the enhanced value of dielectric constant [39]. Although the 7
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
extrinsic effects based on the inhomogeneous microstructures and the subsequent interfacial polarization, such as the Maxwell–Wagner effect, should contribute significantly to the giant dielectric response at lower frequencies, the high frequency giant dielectric response in the present
cri pt
material should originate from some intrinsic mechanisms since no extrinsic mechanism can be expected to be valid at such high frequencies [27].
The doped La2NiO4 display reduced values of the dielectric constant compared to the parent
one but in all the doped cases, the remnant dielectric constant after 1 MHz is still in the range of 104.
Since these materials are applicable to the gigahertz application, the lower retained dielectric constant in the present samples can be due to the porous nature of the sample as is clear from the
SEM images given above. The higher values of dielectric constant at lower frequencies and initially
us
sharp decrease in the said value can be due to space charge polarization and could be explained via
Koop’s model and Maxwell–Wagner polarization theory [30, 41]. The slower change in the dielectric constant with increase in frequency can be attributed to the fact that beyond a certain
an
critical frequency, the electronic exchange between the metal ions starts disobeying the applied field [39-41].
The dielectric loss (tan δ) as a function of log f (Hz) has been displayed in the Figure 10. The
dM
highest value of loss corresponds to the parent material La2NiO4. The low doping shows that loss value was effectively controlled and it approaches to a value of 1 at 1 MHz with higher retained value of dielectric constant exhibited by the samples at 1 MHz. The decrease in dielectric loss tangent with increase in frequency can be explained by Koop’s phenomenological model. The loss in the dielectric constant occurs when the polarization lags behind the applied alternating field. In addition to this, the dielectric loss arises also due to the presence of impurities and structural inhomogeneties
4
pte
[41, 42]. Table 2 represents the dielectric constants and losses at lower and higher frequency range.
Conclusion
The polycrystalline collosal dielectric ortho-nickelates with compositional formulae La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) were prepared through conventional solid state reaction route.
ce
The samples were found to have crystalized in tetragonal structure (I4/mmm) confirmed from XRD analysis followed by the Retvield analysis. The tetragonal structure was witnessed from Raman spectra analysis via stretching of Ni-O bond at ≈ 440 cm-1 and at ≈ 220 cm-1. The FTIR spectra analysis revealed Ni-O and La (Ba/Y)-O-Ni bonds in the synthesized nickelates which confirms the required sample formation. Despite the FESEM micrographs revealing porous nature, higher extent
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
of agglomeration and rarely defined grain boundaries, these samples fulfil the criteria regarding 8
Page 8 of 25
Page 9 of 25
structure and the dielectric nature. This character appeals that these if made compact may show modified dielectric properties. The parent La2NiO4 was found to exhibit dielectric constant in the range of 108 -107 in the frequency range of 105-106 Hz. The minimum doping concentration was
cri pt
found to reduce the dielectric loss to a considerable range with remnant dielectric constant of the
order of ≈105 about 1MHz. The temperature dependent four probe technique for dc resistivity measurement revealed semiconducting nature of the samples with sharp increase in the resistivity about 50K. The present materials with low loss, slow decrease in dielectric constant and stability at higher ac field demonstrates their usability in the Giga hertz applications.
Acknowledgements
us
UGC-DAE-CSR, as an institute is acknowledged for providing characterization facilities.
Authors are thankful to Dr. V. Ganesan, Dr. R. Rawat for low temperature dc resistivity measurements, Dr. M. Gupta for XRD, Dr. Venkatesh and Dr. D. M. Phase for FESEM and EDAX
an
characterizations. Also their guidance and useful discussions are worthy to acknowledge. Thanks to Mr. Lyantha, Mr. V. K. Ahire for their technical support. Authors pay special thanks to Dr. P.
ce
pte
dM
Sharma, School of Chemistry, Devi Ahilya University for providing FTIR facility.
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
9
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
REFERENCES [1]
M. A. Subramanian, D. Li, N. Duan, B. A. Reisner, and A. W. Sleight, J. Solid State Chem., 151 (2000) 323[2] H. Zhao, Q. Li, L. Sun, Sci. China: Chem., 54 (2011) 898−910. J. G. Bednorz, K. A Müller, Z. Physics B: Condens. Matter., 64 (1986) 189−193. [4]
[5]
J. M. Phillips, J. Appl. Phys., 79 (1996) 1829−1848.
cri pt
[3]
Z. Zhu, H. Zeng, J. Li, Z. You, Y. Wang, Z. Huang, Tu. Chaoyang, Cryst. Eng. Comm., 14 (2012) 7423−7427.
J. M. Ralph, A. C. Schoeler and M. Krumpelt, J. Mater. Sci., 36 (2001) 1161.
[7]
Russell J. Woolley, S. J. Skinner, J. Power Sources, 243 (2013) 790–795.
[8]
A. Demourgues, A. Wattiaux, J. C. Grenier, M. Pouchard, J. L. Soubeyroux, P. Hagenmuller, J. Solid State Chem., 105 (1993) 458–468.
us
[6]
S. Skinner, J. Solid State Sci., 5 (2003) 419–426.
[10]
J. H. Huang, X. Y. Jiang, X. B. Li, A. Q. Liu, J. Electroceram. 23 (2009) 67–71.
[11]
C.H. Mu, P. Liu, Y. He, J.P. Zhou, H.W. Zhang, J. Alloys Compd., 471 (2009) 137–141.
[12]
J. B. Wu, C. W. Nan, Y. H. Lin, Y. Deng, Phys. Rev. Lett., 89 (2002) 217601.
[13]
Y. Xiao, X. M. Chen, X. Q. Liu, J. Electroceram., 21 (2008) 154–159.
[14]
C. C. Homes, T. Vogt, S. M. Shapiro, S. Wakimoto, A. P. Ramirez, Science., 293 (2001) 673–676.
[15]
L. Ni, X. M. Chen, Appl. Phys. Lett., 91 (2007) 122905 and T. Park, Z. Nussinov, K. R. A. Hazzard,
dM
an
[9]
V. A. Sidorov, A. V. Balatsky, J. L. Sarrao, S. W. Cheong, M. F. Hundley, J. S. Lee, Q. X. Jia, J. D.
[16]
pte
Thompson, Phys. Rev. Lett., 94 (2005) 017002.
X. Q. Liu, S. Y. Wu, X. M. Chen, H. Y. Zhu, J. Appl. Phys., 104 (2008) 054114 and V. Sachan, D. J. Buttrey, J. M. Tranquada, J. E. Lorenzo, G. Shirane, Phys. Rev. B., 51 (1995) 12742. C. L. Song, Y. J. Wu, X. Q. Liu, X. M. Chen, J. Alloys Compd., 490 (2010) 605–608.
[18]
X. C. Fan, X. M. Chen, X. Q. Liu, Chem. Mater., 20 (2008) 4092–4098.
[19]
S. H. Han and M. B.Maple, Phys. Rev. B., 52 (1995) 1347.
[20]
A. M. Hernandez, J. V. Castillo, L. Mogni, A. Canneiro, Int. J. Hydrog. Energy., 36 (2011) 15704.
ce
[17]
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
[21]
G. Amow, I. J. Davidson , S.J. Skikinner, Solid State Ion., 177 (2006) 1205. 10
Page 10 of 25
Page 11 of 25
M. Saleem, D. Varshney, J. Alloys Compd., 708 (2017) 309
[23]
J. Rodriguez - Carvajal, Physica B, 192 (1993) 55
[24]
G. Gouadec, Ph. Colomban, N. P. Bansal, J. Am. Ceram. Soc., 84 (2001) 1136-1142.
[25]
C. Prieto, A. de Andres, M. Medarde, Solid State Commun.,80 (1991) 975-980.
[26]
M. Udagawa, H. Hata, S. Nimori, T. Minami, N. Ogita, S. Sakita, F. Nakamura, T. Fujita and Y.
cri pt
[22]
Maeno, J. Phy. Soc. J., 67 (1998) 2529-2533. [27]
T. B. Adams, D. C. Sinclair, and A. R. West, J.Am. Ceram. Soc. 89 (2006) 3129and D. P. Huang, Q. Xu, F. Zheng, W. Chen, H. Liu, J. Zhou, Mater. Lett., 60 (2006) 1892.
X. Weng, P. Boldrin, I. Abraham, S. T. Skinner, S. Kellici, J. A. Darr, J. Solid State Chem., 181
us
[28]
(2008) 1123. [29]
P. K. Siwach, R. Prasad, A. Gaur, H. K. Singh, G. D. Varma and O. N. Srivastava, J. Alloys Compd.,
an
20 (2007) 1-43.
M. Saleem and D. Varshney, RSC Adv., 8 (2018) 1600.
[31]
N. Ogita, M. Udagawa, I. Kojima, J. Phy. Soc. Jpn, 57(1989) 3982
[32]
J. Liu, Z. Zhao, C. Xu, A. Duan, T. Meng, X. Bao, Catal Today, 119 (2007) 267
[33]
A. Demourgues, P. Dordor, J. P. Doumerc, J. C. Grenier, E. Marquestaut, M. Pouchard, A.
dM
[30]
Villesuzanne and A. Wattiaux, J. Solid State Chem., 124 (1996) 199. [34]
J. M. Rubinstein, J. Appl. Phys., 87 (2000) 5019 and T. Katsufuji, T. Tanabe, T. Ishikawa, Y. Fukuda, T. Arima and Y. Tokura Phys. Rev. B, 54 (1996) 230. S. Sankal and C. Kaynak, J. Reinf. Plast. Compos., 32 (2013) 75.
[36]
G. J. Snyder, R. Hiskes, S. Dicarolis, M. R. Beasley, T. H. Geballe, Phys. Rev. B,53 (1996) 14434.
[37]
N. F. Mott and E. A. Davis, Electronics Process in Noncrystalline Materials. Oxford, U.K.:
pte
[35]
Clarendon Press, 1979.
C. Y. Shi, B. Hu, Y. M. Hoa, J. Alloys. Comp., 509 (2011) 1333.
[39]
K. W. Wagner, Ann Phys., 40 (1913) 817.
[40]
C. G. Koops, Phys Rev., 83 (1951) 121.
ce
[38]
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
[41]
S. Krohns, P. Lunkenheimer, C. Kant, A. V. Pronin, H. B. Brom, A. A. Nugroho, M. Diantoro, and A. Loidl, Appl. Phys. Lett., 94 (2009) 122903. 11
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
pte
dM
an
us
cri pt
C. C. Homes, T. Vogt, S. M. Shapiro, S. Wakimoto, and A. P. Ramirez, Science, 293, (2001) 673.
ce
[42]
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
12
Page 12 of 25
Page 13 of 25
Figure Captions
cri pt
Figure 1: XRD spectrum La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) samples. Figure 2: Rietveld refinement of X-ray diffraction data for La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) nickelates.
Figure 3: Crystal structure of the pristine (a) La2NiO4 and (b) La1.9Y0.05Ba0.05NiO4 sample. Figure 4: Raman spectra of La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) samples.
Figure 5: EDAX spectra of La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) nickelates.
us
Figure 6: FESEM micrographs of the prepared nickelates.
Figure 7: FTIR plots for the nickelates under investigation.
an
Figure 8: Temperature dependent dc resistivity measurements of the prepared samples. Figure 9: Dielectric constant as a function of log f (Hz) for pristine and doped La2NiO4.
ce
pte
dM
Figure 10: Dielectric loss as a function of log f (Hz).
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
13
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
Table 1 Table 1: Details of Rietveld refinements of La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) samples.
La1.95Y0.05NiO4
La1.90Ba0.05Y0.05NiO4
I4/mmm 3.851(2) 3.862(3) 12.686(3) 189.197(3) 6.945 9.96 13.70 53.0 44.6 30.4 2.158 1.5
I4/mmm 3.854(3) 3.85(2) 12.67(2) 188.25(2) 5.987 8.28 14.4 59.2 47.9 28.7 2.788 1.7
I4/mmm 3.857(2) 3.85(2) 12.69(2) 188.397(3) 6.887 7.92 12.2 54.5 42.9 27.1 2.509 1.7
an
us
La2NiO4
ce
pte
dM
Parameters Space group a (Å) b( Å) c( Å) V (Å3) Density (g/cm3) RF RBragg Rp Rwp Rexp χ2 GOF
cri pt
Values of structural parameters obtained after Rietveld refinement
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 14 of 25
14
Page 15 of 25
At 1.25×105 Hz
At 1 MHz
La2NiO4
2.2x107
1.1x105
2
La1.95Y0.05NiO4
8.7x104
1.9x102
3
La1.90Ba0.05Y0.05NiO4
9.6x105
1.3x104
At1.25×105 Hz
At 1 MHz
87.1
3.83
5.52
1.04.
22.4
2.27
ce
pte
dM
an
us
1
cri pt
Table 2: Dielectric constant and dielectric loss values for La2NiO4, La2-x Yx-y BayNiO4 (x = 0.1, y = 0.0, 0.05) samples. Sr.No. Sample Name Dielectric Constant (έ) Dielectric loss Tan δ
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
15
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
Figure 1
cri pt
La1.9Y0.05Ba0.05NiO4 La1.9Y0.1NiO4
40
50
2(degree)
ce 16
60
70
224 303208 310
118 220
215
us
30
211 116 204 107 213
200
an 105 114
110
dM
20
pte
10
101
002
103
Intensity (a.u.)
La2NiO4
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 16 of 25
80
Page 17 of 25
cri pt
Figure 2
Yobs Ycalc Bragg_position Yobs-Ycalc
Yobs Ycalc Bragg_position Yobs-Ycalc
La2NiO4
La1.95Y0.05NiO4
20
30
40
50
60
70
80
90
10
20
30
40
an
2(degree)
us
Intensity (arb. units)
Intensity (arb.units) 10
50
2(degree)
Yobs Ycalc Bragg_position Yobs-Ycalc
dM
Intensity (arb. units)
La1.90Ba0.05Y0.05NiO4
20
30
40
50
60
2(degree)
ce
pte
10
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
17
70
80
60
70
80
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
dM
an
us
cri pt
Figure 3:
(b) 3D-View for Y/Ba doped La2NiO4
ce
pte
(a) 3D-View for La2NiO4
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
18
Page 18 of 25
Page 19 of 25
cri pt
438 cm
221 cm
-1
-1
Figure 4
La1.9Y0.1NiO4
600
La2NiO4
800
-1
Raman Shift (cm )
ce
pte
dM
400
an
-1
438 cm
-1
225 cm
200
us
437 cm
222 cm
-1
-1
Intensity (a.u.)
La1.9Y0.05Ba0.05NiO4
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
19
1000
1200
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
cri pt
Figure 5
La2NiO4
an
us
La1.95Y0.05NiO4
ce
pte
dM
La1.9Ba0.05Y0.05NiO4
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 20 of 25
20
Page 21 of 25
Figure 6
L La2NiO4 a2NiO4
pte
dM
an
us
cri pt
La1.95Y0.05NiO4
ce
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
21
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
cri pt
Figure 7
492.07 (A2u)
647.62 (E2u)
us
637.76 (E2u)
1000
1500
2000
2500
dM
500
an
La2NiO4
646.5 (E2u)
488.56 (A2u)
La1.9Y0.1NiO4
496.23 (A2u)
% Transmittance
La1.9Y0.05Ba0.05NiO4
3000 -1
ce
pte
Wavenumber (cm )
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 22 of 25
22
3500
4000
Page 23 of 25
Figure 8
1800
La2NiO4 (0T)
600
1200
500
1400
1000
400
1200
300
La2NiO4 (8T) 300
200
100
200 0
100
0
50
100
150
200
250
Temperature (K)
50
100
150
200
250
600
0 0
400
-200
300
50
100
0
50
100
2000
1000
150
La1.9Y0.05Ba0.05NiO4 (8T)
dM
Resistivity [ (-m)]
1200
1500
1000
800 600 400 200
0
500
-200
50
pte
0
0
50
100
150
150
200
Temperature (K)
200
Temperature (K)
ce
0
100
200
23
250
250
200
Temperature (K)
an
1400
150
250
300
Temperature (K)
La1.9Y0.05Ba0.05NiO4 (0T)
2500
Resistivity [ (-m)]
400
200
Temperature (K)
Ac
600
800
0 0
La1.9Y0.1NiO4 (8T)
200
300
0 -100
1000
800
us
400
Resistivity [ (-m)]
Resistivity [ (-m)]
600
Resistivity [ (-m)]
1600
700
500
La1.9Y0.1NiO4 (0T)
cri pt
800
Resistivity [ (-m)]
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
300
300
250
300
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
cri pt
Figure 9
7
1.2x10
6
1.0x10
La1.9Y0.1NiO4
7
1.0x10
La1.9Y0.05Ba0.05NiO4
5
6
8.0x10
6
5
4.0x10
5
2.0x10
an
6.0x10
5
6.0x10
us
Dielectric Constant (')
Dielectric Constant (')
8.0x10
6
4.0x10
0.0
5.0
6
5.2
dM
2.0x10
5.4
5.6
5.8
Logf (Hz)
6.0
La2NiO4
0.0
5.2
5.4
5.6
Logf (Hz)
ce
pte
5.0
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
Page 24 of 25
24
5.8
6.0
Page 25 of 25
Figure 10
100
25
cri pt
La1.9Y0.1NiO4
La1.9Y0.05Ba0.05NiO4
20
Dielectric Loss (tan)
60
15
10
0 5.0
us
5
40
5.2
5.4
20
La2NiO4
0 5.0
5.4
5.6
Logf (Hz)
ce
pte
dM
5.2
5.6
Logf (Hz)
an
Dielectric Loss (tan)
80
Ac
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
AUTHOR SUBMITTED MANUSCRIPT - MRX2-101298.R2
25
5.8
5.8
6.0
6.0