Effect of Bi3+ ions on the humidity sensitive properties ...

Sensors & Actuators: B. Chemical 272 (2018) 28–33

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Sensors and Actuators B: Chemical journal homepage: www.elsevier.com/locate/snb

Effect of Bi3+ ions on the humidity sensitive properties of copper ferrite nanoparticles Pradeep Chavan, L.R. Naik

T

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Department of Studies in Physics, Karnatak University, Dharwad, 580003, India

A R T I C LE I N FO

A B S T R A C T

Keywords: Humidity sensitivity Relative humidity Copper ferrite nanoparticles Porosity and solution combustion route

The response of humidity sensitivity factor of bismuth substituted copper ferrite nanoparticles is prepared by solution combustion route by using metal nitrates. From this preparation technique, bismuth substituted copper ferrites were confirmed to demonstrate the cubic spinel structure by X-ray diffraction measurement and FTIR spectral absorption bands observed at ν1 = 560 cm−1 to 580 cm−1 and ν2 = 404 cm−1 to 407 cm−1 for tetrahedral and octahedral sites in cubic spinel structure of ferrites. The prepared nanoparticles of ferrites are extremely resistive in the range of mega-ohm (MΩ) at room temperature and their humidity sensitivity is also very high. The electrical resistance is decreased for different concentration of bismuth in copper ferrites, noticeably with increasing the relative humidity. The relative humidity of BixCuFe2-xO4 nanoparticles in the range from 10% RH to 90% RH at room temperature is generated. With the substitution of bismuth, the sensitivity factor is decreased at low relative humidity. The maximum humidity sensitivity factor Sf = 925.64 was achieved for Bi0.1CuFe1.9O4 nanoparticles.

1. Introduction The magnetic materials such as ferrites in some applications like humidity or gas sensors require focusing mainly on their electrical properties rather than magnetic properties [1]. The low cost and easy manufacturing as compared with metallic materials make the ferrite materials very useful in technological applications as permanent magnets, Hall sensors, filters, etc. More than that the electrical and magnetic properties of ferrites can be easily controlled in different ways such as substitution, preparation condition, thermal treatment, etc [2,3]. Therefore, it is known that the adsorption of moisture vapors from the environment on the surface of materials (say ferrites) can cause considerable changes in the conduction mechanism of electrons of the material. Thus, it is very significant to know how the relevant parameters of the materials change their values under the influence of humidity and, if these changes are important, the material in question can be used in applications for moisture detection as humidity sensors [4,5]. The enhancement of scientific applications in modern technology is necessary to build up highly sensitive, steady and less expensive humidity sensors to control the level of humidity for the processing of extremely sophisticated electrical circuits in electronics industry. The inevitability of automated devices increases continuously and requires smart humidity sensors to monitor the ecological surroundings for data

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Corresponding author. E-mail address: naik_40@rediffmail.com (L.R. Naik).

https://doi.org/10.1016/j.snb.2018.05.135 Received 13 January 2018; Received in revised form 20 April 2018; Accepted 23 May 2018 Available online 24 May 2018 0925-4005/ © 2018 Elsevier B.V. All rights reserved.

storage, processing of food, medicinal processing and forecast of weather [6,7]. Several synthesized materials have been considered for the accomplishment of high humidity sensing property which depends on the condition of the atmosphere. Instead of all the materials, ceramic oxides are found better in terms of stability, less expensive and their performance in broad operating range, etc. For the most part, spinel type ceramic oxides have been used as humidity sensors because of their high resistivity and steady structure [8]. Numerous remarkable chemical and physical phenomena which can take place on the surface of metal oxide ceramic materials rely on the surface of conduction of electrons and their structure of pores. The adsorption of water vapour takes place on the surface of ceramic materials because of the chemical reactivity of porous materials; thus, in turn, the conductivity increases [9]. Accordingly, the increase of DC electrical conductivity of the porous materials with respect to humidity sensitivity was due to the chemisorption and physisorption of the water vapours on the surface of porous materials [10]. The ferrites with cubic spinel structure have the tetrahedral structure with high density of defects and they have semiconducting behavior in nature. Polycrystalline ferrites have the porous assembly of n-type semiconducting materials. When water vapours brought near to the n-type semiconducting materials surface, the electrons near to the surface are transferred from conduction band to the electron accepting level of water molecules, which gives the chemisorbed layer of OH− ions. The conduction of


P. Chavan, L.R. Naik

electrons takes place when H3O+ release one proton to the nearest water molecule and that accepts electrons while releasing another proton, and so on [11]. This process is known as Grotthuss chain reaction. This chain reaction is the basic conduction mechanism of water and surface layers of water on the humidity sensitive materials [11]. In the present paper, humidity sensing properties of BixCuFe2-xO4 (x = 0.0, 0.1, 0.2, 0.3, 0.4 & 0.5) samples prepared by solution combustion route were studied. The substitution of bismuth ions in copper ferrites was due to the reduction of defects and porosity in the spinel structure of ferrites. This suggests that the substitution of bismuth ions was due to the improvement of the growth of smaller grains of copper ferrites, leading to the surface area and enhanced the humidity sensing properties of ferrites. The humidity sensitivity of the ferrite samples was studied on the basis of microstructure and conduction mechanism of electrons of the cubic spinel structure of ferrite nanoparticles.

The frequency dependence of dielectric constant and AC conductivity was measured at room temperature using LCR meter bridge (Model: PSM1700). The response of DC resistivity to relative humidity was measured by two probe method in the range from 10% to 90% RH at room temperature. The relative humidity is generated by two pressure technique in the relative humidity generator on the basis of the following relation:

%RH =

Pa × 100 Ps

(1)

where Pa = actual pressure of water vapor at room temperature and Ps = saturation pressure of water vapor. The humidity sensitivity factor of the ferrite samples was estimated by the following relation:

Sf = 2. Role of sucrose and polyvinyl alcohol (PVA)

R90% R10%

(2)

The porosity of the ferrite samples was estimated using the relation: During the preparation of ferrite nanoparticles, sucrose provides wrapping through co-ordination for the cations in solution and works as a chelating agent as well as the atomistic distribution of cations throughout the polymeric network structure Sucrose behaves like a fuel for combustion reaction by the oxidation of nitrate ions. Polymeric stability of nitrate ions is due to the formation of chemical bonding between the cations in polymeric chain and formation of extremely high viscosity polymeric solution. Though, the chemical bonding is demolished during pyrolysis, the high viscosity ensures low cation mobility and helps for the nanocrystalline (agglomerate) morphology of the ferrites. 30 g of sucrose were dissolved in 50 mL of distilled water and the solution was heated on a magnetic stirrer at the temperature of about 80 °C. The clear sucrose solution is used a chelating agent during the preparation of ferrite nanoparticles. Polyvinyl Alcohol (PVA) is a polymer material which is used as a binding agent during the sample preparation. PVA solution is mixed with the powder samples because metal ions bind together which creates bonding between the metal ions. Thus, 2 g of PVA were dissolved in 10 mL distilled water and the solution was heated on magnetic stirrer; we get 20% of PVA solution. This prepared PVA solution is used as a binder during the pelletization of the ferrite powder samples.

%P = 1 −

da × 100 dx

(3)

where da = actual density of the samples, dx = X-ray density. The lattice constant of the ferrites was estimated using the relation: 1

a = d × (h2 + k 2 + l 2)

2

(4)

where d = interplanar spacing, hkl are the miller indices. The DC resistivity as a function of temperature was estimated by using the relation:

ρ=

RA t

(5)

where R = resistance, A = area of the pellet, t = thickness of the pellet samples. 4. Results and discussion X-ray diffraction pattern of annealed ferrite samples were carried out between the 2theta angles ranging from 20° to 80°. The phase formation of bismuth substituted copper ferrites was confirmed by Xray diffraction measurement. From Fig. 2, the peaks observed from Xray diffraction pattern confirmed the cubic spinel structure of bismuth substituted copper ferrites and all peaks were indexed with the help of ASTM data as shown in Fig. 2. The crystallite size estimated by using Scherrer formula:

3. Experimental details Analytical reagent grade materials of high purity metal nitrates Cu (NO3)2, Bi(NO3)3 and Fe(NO3)3 are taken in a stoichiometric proportion and dissolved in 50 mL deionized water for standardized assortment. 10% of PVA solution was assorted with hot sucrose solution and stirred on the magnetic stirrer for clear solution. All the solutions prepared were assorted together and then heated on the magnetic stirrer at the appropriate temperature until NO2 vapours vanished completely and a gelatinous assortment was formed. This assortment was heated on the gas burner until it burns like live charcoal undergoing combustion reaction for the configuration of ferrite nanoparticles in powder form. The powder was presintered at 600 °C for 8 h in the muffle furnace and cooled to room temperature. 2% of PVA was added to this powder which acts as a binding agent and then hard-pressed into the form of pellets using the hydraulic press. The pellets were finally sintered at 800 °C for 10 h and then furnace cooled to room temperature. The preparation process was mentioned in Fig. 1. The phase formation of the ferrites was confirmed by X-ray diffraction measurement. X-ray diffraction measurement was carried out by X-ray Diffractometer with Cu-Kα radiation and wavelength of 0.15406 nm. The surface morphology and microstructure of ferrite nanoparticles were carried out by SEM measurement (Model: JEOL-JSM 6360). FTIR studies were carried out by FTIR spectrophotometer (Model: NICOLET 6700). DC electrical resistivity with respect to temperature was measured by two probe method (Digital Multimeter, Model: Keithley 2000).

D=

0.89λ βcosθ

(6)

where λ is the wavelength of the X-rays, β is the full width at half maximum and θ is the Bragg angle. The average crystallite size was determined by using the peaks 31.9°, 35.8°, 45.8°, 57.0° and 62.1°. The crystallite size increases from 16.82 nm to 37.16 nm (Fig. 3) [12]. The confirmation of phase formation of the ferrites by X-ray diffraction measurement rests on the precise measurement of lattice constant. The lattice constant estimated from the prepared ferrite nanoparticles by solution combustion route are found to be 0.832 nm and gradually increased by the substitution of bismuth in copper ferrite nanoparticles (Fig. 3) [13]. Fig. 4 shows the SEM image of pure copper ferrite nanoparticles prepared by solution combustion route. The ferrite samples were finally sintered at a temperature of 800 °C for 10 h; the SEM image was taken for the sintered powder samples. The allocation of average grain size of pure copper ferrite nanoparticles was predicted by Cottrell’s method or line intercept method on SEM micrograph. From the analysis of the microstructure of ferrite nanoparticles, the average grain size of pure copper ferrites was obtained in the range from 163 nm to 245 nm. The average grain size of pure copper ferrite nanoparticles 29



Fig. 1. Preparation process of bismuth substituted copper ferrite nanoparticles.

Fig. 4. SEM Micrograph of copper ferrite sample. Fig. 2. XRD pattern of copper ferrite samples added with different amount of bismuth.

Table 1 Structural and physical characteristics of bismuth substituted copper ferrites. x Content

Average Crystallite Size (nm)

Lattice Constant (nm)

% Porosity

Sensitivity Factor

0.0 0.1 0.2 0.3 0.4 0.5

16.82 18.04 21.56 24.51 29.65 37.16

0.832 0.794 0.815 0.842 0.855 0.879

21.5 19.8 19.3 17.8 15.6 13.5

815.65 925.64 705.154 615.946 302.154 256.456

and porosity of the prepared ferrite samples are found in the range from 163 nm to 245 nm and 21.5% to 13.5%. Thus, the permutation of mesopores and micropores are coupled through the neck of grains over the entire surface of ferrites are predominantly noticeable in SEM image of ferrite nanoparticles [12]. The% of porosity of BixCuFe2-xO4 nanoparticles are summarized in Table 1. Bismuth substituted copper ferrites are characterized by Fourier transform infrared (FTIR) spectroscopy as shown in Fig. 5. The IR spectrum reveals the ordered cubic spinel structure of ferrites. It is clear that two absorption bands were observed below 600 cm−1 are the universal features of cubic spinel structure of ferrite materials [15]. Thus, from the IR spectra of bismuth substituted copper ferrite samples, high frequency band observed in the range from

Fig. 3. Variation of crystallite size and lattice constant of bismuth substituted copper ferrite nanoparticles.

determined from this technique is smaller as compared to other techniques like solid state reaction route. The morphology of the ferrite nanoparticles reveals that the grains are well connected through the necks of other grains of the ferrite samples [14]. The average grain size 30



Fig. 7. Variation of dielectric constant with respect to frequency of bismuth substituted copper ferrite nanoparticles.

Fig. 5. IR spectra of copper ferrite samples added with different amount of bismuth nitrate.

ν1 = 560 cm−1 to 580 cm−1 and the low frequency band observed in the range from ν2 = 404 cm−1 to 407 cm−1. This difference observed in band position of IR spectra of ferrite nanoparticles was due to the vibration of tetrahedral and octahedral sites in the cubic spinel structure. From Fig. 5, it is observed that the absorption bands slightly shift their location by the addition of bismuth in copper ferrites was due to the change in the Fe3+ − O2− complex ions with the increase of bismuth ions [16]. The variation of DC resistivity as a function of the temperature of BixCuFe2-xO4 nanoparticles is shown in Fig. 6. Thus, the decrease of DC resistivity with respect to the temperature shows the semiconducting behavior of the ferrites. Verwey de-Boer mechanism [17] explained that the electrical conductivity is dependent on the exchange of electrons among the ions of the identical elements exists in more than one valence state and indiscriminately spread over the crystallographical lattice sites in ferrites. However, the mechanism of conduction of electrons was explained on the basis of hopping of electrons between the ions of Fe2+ and Fe3+ (n-type semiconductors) and the hopping of holes between the ions of Cu2+ and Cu3+ (p-type semiconductors) [18]. Thus, the electrical conductivity of ferrite nanoparticles obeys Arrhenius relation: σ = σ0 exp ΔE kT , where ΔE = activation energy, k = Boltzmann constant, σ0 = constant of materials and T = absolute temperature. The consequence of frequency of the dielectric constant of BixCuFe2xO4 nanoparticles is shown in Fig. 7. It is clear that the decrease of dielectric constant with an increase in frequency was observed in BixCuFe2-xO4 nanoparticles reveals the standard dielectric dispersion

behavior of the spinel ferrites [19]. Iwauchi [20] explained that there is a powerful correlation between dielectric properties and conduction mechanism of the ferrites. The exchange of electrons among Fe2+ ↔ Fe3+ at nearest neighboring octahedral sites results in the local dislocation of electrons in the direction of the functional electric field. This displacement of electrons shows the polarization in ferrite samples. The dielectric constant is maximum at subordinate frequency region; it was due to the majority of Fe2+ ions, vacancies of oxygen, defects in grain surface area, etc. The decrease of dielectric constant with increase in frequency was due to the fact that any type of materials contribute to the polarization and shows that it is sheathing behind the applied field at higher frequencies [21]. However, the polarization decreases with increase in frequency and reaches a certain value due to the fact that beyond certain frequency of external field, the frequency of electron exchange between Fe3+ and Fe2+ ions cannot follow the alternating field frequency. The variation of AC conductivity with respect to the frequency of bismuth substituted copper ferrites is shown in Fig. 8. The increase of AC conductivity with an increase in frequency was observed, it is because of the small polaronic effect takes place in spinel structure of ferrite materials [19,22]. The increase of AC conductivity with respect to frequency shows dispersion behavior and this behavior is explained by Koop’s phenomenological theory [23] that the compressed ferrite materials act as a multilayer capacitor. The dielectric materials assumed to consist of well conducting grains separated by inadequately conducting grain boundaries of ferrites. The ferrite grain boundaries are

Fig. 6. Variation of DC electrical resistivity with respect to temperature of Bi substituted copper ferrite nanoparticles.

Fig. 8. Variation of AC conductivity with respect to frequency of bismuth substituted copper ferrite nanoparticles.

(

)

31



more effective at low frequency with high electrical resistance giving a small increase in AC conductivity. At high frequency region, the AC conductivity increases due to the effect of ferrite grains [24]. Therefore, AC conductivity increases with increase in the frequency of bismuth substituted copper ferrites explained by the hopping of electrons among Fe2+ and Fe3+ ions (n-type) on the octahedral site and it is responsible for the conduction of electrons in the cubic spinel structure of ferrites. However, the increase of AC conductivity with respect to frequency was explained by Maxwell-Wagner type of interfacial polarization theory and this is in good agreement with Koop’s phenomenological theory [25,26]. Thus, there are two types of polarons in ferrites which are responsible for the conduction of electrons. They are small polarons and large polarons. In case of small polarons, the AC conductivity increases with increase in frequency and in case of large polarons, the AC conductivity decreases with increase in frequency. Therefore, the bismuth substituted copper ferrite nanoparticles shows small polarons model [27]. The control of porosity and surface activity of the materials is of most important concern for ionic type humidity sensor devices, since they rely on surface correlated effects. Therefore, high porosity and large surface area are advantageous to improve the sensitivity, in so far as they do not compromise mechanical stability. Thus, in order to acquire a good humidity-sensitive response, the resistivity of the materials must be high in a dry environment and their porosity as well as pore size distribution must be controlled. A theoretical model for the estimation of impedance humidity uniqueness is based on the use of Kelvin’s equation [28]. The response of electrical resistivity with respect to the relative humidity of the ferrite samples was measured from 10% to 90% RH at room temperature. For resistance measurement, a DC bias of about 1 V ± 0.0001 was applied across the electrodes of the ferrite samples. For RH measurements at room temperature, the humidity sensitivity was varied in the steps of 10% RH (10–90% RH) by taking 10 min time in every step and 5 min was permitted to acquire the steady reading of samples resistance. This process was followed by both up and down cycles of a standard relative humidity generator at room temperature. From Fig. 9, it is clear that the humidity sensitivity of the ferrite samples decreases with increasing bismuth concentration in copper it is because of the metal ions effortlessly contributes the conduction of electrons in ferrites and provided the change in local charge density on the bulk surface to the water vapours [6,29]. Thus, bismuth ions uptakes oxygen ions from the copper ferrites by leaving Cu2+ ions in bulk form and it shows that an augmented number of well organized adsorption sites gives elevated surface charge [10]. Therefore, the bismuth ions provide the sites of valences on the

Fig. 10. log R vs bismuth concentration of bismuth substituted CuFe2O4 samples.

surface of ferrite samples and then humidity sensitivity is high at low relative humidity. From Fig. 9, it is observed that electrical resistivity decreases with increase in relative humidity and electrical resistivity is extreme at Bi0.4CuFe1.6O4 (Fig. 10). This reveals that the connectivity between the intergrain is very good and surface area is high, it was due to the smaller grains of ferrites with sufficient porosity resulting in the chemisorption and physisorption of water vapors [9,30]. Therefore, the estimated value of sensitivity factor of bismuth substituted copper ferrite nanoparticles were listed in Table 1. The sensitivity factor of ferrite samples was found to be maximum at Bi0.1CuFe1.9O4 i.e. Sf = 925.64 among all the ferrite samples shown in Fig. 11. The sensitivity factor of the ferrites is low at Bi0.5CuFe1.5O4, it was due to the larger grains, less porosity and lower surface charge i.e. advantageous for high humidity sensing property of the ferrites [10,31,32]. 5. Conclusion The effect of bismuth in copper ferrite nanoparticles prepared by solution combustion route having cubic spinel structure and Fd3 m space group was studied for the measurement of humidity sensing. It was observed that the particles of nanosize scale were formed by this synthesis route. The observed difference in crystallite size distribution was due to the bismuth ion substitution in copper ferrites. The conduction mechanism has been studied using DC resistivity of the ferrite nanoparticles. The decrease of dielectric constant with increase in frequency shows dielectric dispersion behavior. The linear increase of AC

Fig. 9. log R vs relative humidity of pure and bismuth substituted CuFe2O4 samples.

Fig. 11. Sensitivity factor vs bismuth concentration of bismuth substituted copper ferrite samples. 32



conductivity with frequency of the ferrite nanoparticles was due to the small polaron type of conduction mechanism. Hence, the humidity sensitivity decreased with increasing the bismuth ion concentration in copper ferrite nanoparticles. Therefore, the humidity sensitivity was found maximum Sf = 925.64 for Bi0.1CuFe1.9O4 ferrite samples.

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Acknowledgements I am thankful to the Associate Director, Manipal Institute of Technology, Manipal for providing XRD data on time. I am grateful to UGC for awarding Rajiv Gandhi National Fellowship for the year 201617 to carry out the research work. References [1] F. Tudorache, P.D. Popa, M. Dobromir, F. Iacomi, Studies on the structure and gas sensing properties of nickel-cobalt ferrite thin films prepared by spin coating, J. Mater. Sci. Eng. B 178 (2013) 1334–1338. [2] I. Petrila, F. Tudorache, Humidity sensor applicative material based on copper-zinctungsten spinel ferrite, Mater. Lett. 108 (2013) 129–133. [3] P. Pascariu, A. Airinei, N. Olaru, I. Petrila, V. Nica, L. Sacarescu, F. Tudorache, Microstructure, electrical and humidity sensor properties of electrospun NiO-SnO2 nanofibers, Sens. Actuators B 222 (2016) 1024–1031. [4] F. Tudorache, I. Petrila, Effects of partial replacement of Iron with Tungsten on microstructure electrical, magnetic and humidity properties of copper-zinc ferrite material, J. Electron. Mater. 43 (2014) 3522–3526. [5] N. Rezlescu, E. Rezlescu, F. Tudorache, P.D. Popa, MgCu nanocrystalline ceramic with La3+ and Y3+ ionic substitutions used as humidity sensor, J. Optoelectron. Adv. Mater. 6 (2004) 695–698. [6] M. Li, X.L. Chen, D.F. Zhang, W.Y. Wang, W.J. Wang, Humidity sensitive properties of pure and Mg-doped CaCu3Ti4O12, Sens. Actuators B Chem. 147 (2010) 447–452. [7] E. Rezlescu, N. Rezlescu, F. Tudorache, P.D. Popa, Effects of repalcing Fe by La or Ga in Mg0.5Cu0.5Fe2O4. humidity sensitivity, J. Magn. Magn. Mater. 272 (2004) E1821–E1822. [8] A.Y. Lipare, P.N. Vasambekar, A.S. Vaingankar, Dielectric behavior and a.c. resistivity study of humidity sensing ferrites, Mater. Chem. Phys. 81 (2003) 108–115. [9] T.J. Harpster, B. Stark, K. Najafi, A passive wireless integrated humidity sensor, Sens. Actuators A Phys. 95 (2002) 100–107. [10] J. Shah, R.K. Kotnala, Humidity sensing exclusively by physisorption of water vapors on magnesium ferrite, Sens. Actuators B Chem. 171–172 (2012) 832–837. [11] R.K. Kotnala, J. Shah, B. Singh, H. Kishan, S. Singh, S.K. Dhawan, A. Sengupta, Humidity response of Li-substituted magnesium ferrite, Sens. Actuators B Chem. 129 (2008) 909–914. [12] Pradeep Chavan, Investigation of energy band gap and conduction mechanism of magnesium substituted nickel ferrite nanoparticles, Phys. Status Solidi A (2017) 1–8 (1700077). [13] Pradeep Chavan, L.R. Naik, P.B. Belavi, G. Chavan, C.K. Ramesha, R.K. Kotnala, Studies on electrical and magnetic properties of Mg-substituted nickel ferrites, J. Electron. Mater. 46 (2017) 188–198. [14] P.B. Belavi, G.N. Chavan, L.R. Naik, R. Somashekar, R.K. Kotnala, Structural, electrical and magnetic properties of cadmium substituted nickel-copper ferrites, Mater. Chem. Phys. 132 (2012) 138–144. [15] Pradeep Chavan, L.R. Naik, P.B. Belavi, G.N. Chavan, R.K. Kotnala, Synthesis of Bi3+ substituted Ni-Cu ferrites and study of structural, electrical and magnetic properties, J. Alloys Compd. 694 (2017) 607–612. [16] C.R. Vestal, Z.J. Zhang, Effects of surface coordination chemistry on the magnetic properties of MnFe2O4 spinel ferrite nanoparticles, J. Am. Chem. Soc. 125 (2003)

Pradeep Chavan I am Mr. Pradeep Chavan secured first class at M.Sc. from Dept. of Physics, Karnatak University Dharwad in the year 2012. After completion of M.Sc degree, I am joined for research (Ph.D) in Dept. of Physics, Karnatak University Dharwad under the guidance of Dr. L R Naik, on the topic entitled “Multiferroic Properties of Some ME composites” during the year 2013. Thrust areas of research include materials science and nanotechnology. During the Ph.D course, I am awarded Junior Research Fellow under UGC UPE fellowship, Junior Research Fellow under UGC-RGNF fellowship-2016 and also honored with YOUNG SCIENTIST AWARD-2016 through 12th Karnataka Science Congress organized by Karnataka Veterinary, Animal and Fisheries Sciences University, Bidar, Karnataka. I am published ten research articles in reputed peer reviewed journals and presented several research articles in national and international conferences/symposia. I am synthesized different types of ferrite nanoparticles and magnetoelectric composites as they have potential applications in electronic technology such as storage devices, sensors and treatment for hyperthermia, etc.

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