# Electrical Properties of Ni0.4Mg0.6Fe2O4 Synthesized by Conventional Solid-State Reaction Method

K T Veeranjaneaya, D T Ravinder

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K T Veeranjaneaya, D T Ravinder. Electrical Properties of Ni0.4Mg0.6Fe2O4 Synthesized by Conventional Solid-State Reaction Method. Mechanics, Materials Science & Engineering MMSE Journal. Open Access, 2017, 9, 10.2412/mmse.28.98.879. hal-01504756

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Submitted on 10 Apr 2017

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<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
**Results and Discussion.** The variation of intensity (I) as a function of two-theta (2θ) angle for Ni₀.₄Mg₀.₆Fe₂O₄ is shown in Fig.1. The reflection planes indexed in diffraction pattern show the formation cubic spinel structure. These are in well agreement with the standard JCPDS file number: 74-1913. The (311) plane shows the maximum intensity of 8000 among all cubic phase. The average crystallite size (D) of (311) plane is (96 nm) calculated using the Scherrer formula [13, 14]:

<figure><img src="image_2.png" /><figcaption>Fig. 1. XRD pattern of Ni₀.₄Mg₀.₆Fe₂O₄.</figcaption></figure>

<figure><img src="image_3.png" /><figcaption>Fig. 2. SEM photos of Ni₀.₄Mg₀.₆Fe₂O₄.</figcaption></figure>

The lattice constant is evaluated using a standard formula: a = (h²+ k²+ l²)¹/². The attributed value is of 0.8376 nm which is almost in close agreement with the reported lattice constant 0.839 nm by Naidu et al. [1]. The x-ray density ρₓ is calculated by an equation: ρₓ= 8M/Na³ where M is the molecular weight, N is the Avogadro's number (6.023x10²³ atoms/mole) and 'a' is the lattice parameter computed. The result showed that it is order 4.925 g/cm³. The bulk density ρb is evaluated by using the Archimedes principle and it is found to be 4.023 g/cm³. Furthermore, the porosity is calculated using the relation P = 1-(ρb/ρₓ) and it is of 18.3 %. The low percentage of porosity expresses a fact that the ferrite sample is of high pure in nature. It is obvious from Fig. 2 that the spherical shaped grains are uniformly distributed within the 10 micron area of the spot on the pellet surface. The average grain size (Gₐ) is found to be 2.68 µm using linear intercept method [15].

Fig.3 shows the variation of dielectric constant as a function of temperature at different frequencies. It is seen from the figure that the ferrite composition performs a steady trend during 300 to 500 K temperatures for the selected frequencies. This can be happened due to unavailability of ferrous ions at octahedral B-sites [2]. In addition, the high value of dielectric constant is established at lower frequency and it is low at higher frequencies. The Maxwell-Wagner interfacial or space charge polarization is also responsible for this manner [19]. The similar behavior is observed in the literature [16-18]. The ferrite expresses a small step like increase of dielectric constant at 700 K for 50 kHz and 0.1 MHz frequencies. This is because of jumping of charge carriers at that particular temperature. The loss is also performing the similar trend as that of dielectric constant as shown in Fig. 4. In over all the ferrite composition reveal low value of dielectric constant and loss at higher frequencies. This may be useful for low noise device applications [20, 21].
<figure><img src="image_4.png" /><figcaption>Fig. 3. Temperature Vs. dielectric constant.</figcaption></figure>

<figure><img src="image_5.png" /><figcaption>Fig. 4. Temperature Vs. dielectric loss.</figcaption></figure>

Fig. 5 shows the temperature and frequency dependence of ac-conductivity of present ferrite composition. The lnσ versus 10³/T plots as shown in Fig. 6 are drawn to find the ac-activation energies of ferrite composition at selected frequencies. In the lnσ versus 10³/T plots two slopes are observed. There are different reasons behind performing two slopes or activation energies. Manjula et al. [22] reported that two slopes are because of change of conduction mechanism before and after Curie-transition temperature (T~c~). Islam et al [23] and Hiti [24] revealed that the slope of gradient line must change on passing through T~c~ due to change of exchange interaction between inner and outer electrons at Curie-transition temperature. The activation energies corresponding to the two slopes are evaluated and listed in Table.1. It is seen that ac activation energies are decreasing with increasing of frequency which may be due to increase of ac-conductivity. The activation energies in paramagnetic region (E~1~) are higher than those in ferri magnetic region (E~2~) (Table.1). Moreover, the change of activation energies can be attributed to the change of conduction mechanism from polaron to hopping as reported by Gabal et al. [5]. The lower activation energies (E~2~) are attributed to magnetic disordering owing to limited availability of charge carriers [6].

<figure><img src="image_6.png" /><figcaption>Fig. 5. Temperature Vs. ac-conductivity.</figcaption></figure>

<figure><img src="image_7.png" /><figcaption>Fig. 6. Arrhenius plots of Ni<sub>0.4</sub>Mg<sub>0.6</sub>Fe<sub>2</sub>O<sub>4</sub>.</figcaption></figure>
<table><caption>Table 1. The two region activation energies at selected frequencies.</caption><thead><tr><th>Frequency</th><th>E<sub>1</sub> (eV) (I)</th><th>E<sub>2</sub> (eV) (II)</th></tr></thead><tbody><tr><td>50 kHz</td><td>0.439</td><td>0.271</td></tr><tr><td>0.1 MHz</td><td>0.410</td><td>0.259</td></tr><tr><td>0.5 MHz</td><td>0.382</td><td>0.211</td></tr><tr><td>1 MHz</td><td>0.318</td><td>0.174</td></tr><tr><td>3 MHz</td><td>0.293</td><td>0.146</td></tr></tbody></table>

The variation of logarithm of ac-conductivity as a function of logarithm of angular frequency at selected temperatures is shown in Fig. 7. It is understood from $logσ$ versus $logω$ plots that the total ac-conductivity is the combination of two terms [6]:

$$ \sigma_{ac}(\omega, T) = \sigma_{dc}(T) + \sigma_{ac}(\omega) \quad (2) $$

where the first term is (DC-electrical conductivity) temperature dependent and independent of frequency.

The exponent values show that 'n' values are achieved to be 0.592, 0.551, 0.398, 0.356, 0.284 & 0.270 for 308, 373, 473, 573, 673 & 773 K respectively.

<figure><img src="image_8.png" /><figcaption>Fig. 7. Frequency dependence of ac-conductivity.</figcaption></figure>

**Summary.** Ni$_{0.4}$Mg$_{0.6}$Fe$_{2}$O$_{4}$ ceramic samples are prepared by conventional double sintering technique. The low dielectric constant and low loss obtained for the present composition is useful for low noise device applications. Two different activation energies reveal the change of conduction mechanism from polaron to hopping conduction.

References

[1] K. Chandra Babu Naidu, W. Madhuri, Journal of Magnetism and Magnetic Materials 420 (2016) 109–116

[2] L. J. Berchmens, R. K. Selvan, P. N. S. Kumar, C. O. Augustin, Journal of Magnetism Magnetic Materials 279 (2004) 103-110

[3] L. J. Berchmens, R. K. Selvan, C. O. Augustin, Materials Letters 58 (2004) 1928-1933
[4] Z. V. Mocanu, M. Airimioaei, C. E. Ciomaga, L. Curecheriu, F. Tudorache, S. Tascu, A. R. Iordan, NN. M. Palamaru, L. Mitoseriu, Journal of Material Science 49 (2014) 3276-3286

[5] Chandra Babu Naidu K., Madhuri W, Materials Chemistry and Physics 181 (2016) 432-443

[6] K. Chandra Babu Naidu and W. Madhuri, International Journal of Applied Ceramic Technology, 1-6 (2016), DOI:10.1111/ijac.12571

[7] H. Moradmard, S. F. Shayeshtech, P. Tohidi, Z. Abbas, M. Khalegi, Journal of Alloys and Compounds 650 (2015) 116-122

[8] M. Naeem, N. A. Shah, I. H. Gul, A. Maqsood, Journal of Alloys and Compounds 487 (2009) 739-743

[9] Mirela Airimioaei, Mircea Nicolae Palamaru, Alexandra Raluca Iordan, Patrick Berthet, Claudia Decorse, Lavinia Curecheriu and Liliana Mitoseriu, Journal of American Ceramic Society 97 (2014) 519-526

[10] K. Chandra Babu Naidu, T. Sofi Sarmash, M. Maddaiah, P. Sreenivasula Reddy, D. Jhansi Rani and T. Subbarao, Journal of The Australian Ceramic Society 52 (2016) 95 - 101

[11] K. Chandra Babu Naidu, T. Sofi Sarmash, V. Narasimha Reddy, M. Maddaiah, P. Sreenivasula Reddy and T. Subbarao, Journal of The Australian Ceramic Society 51 (2015) 94 - 102

[12] V. Narasimha Reddy, K. Chandra Babu Naidu, T. Subba Rao, Journal of Ovonic Research 12 (2016) 185-191

[13] M. Maddaiah, A. Guru Sampath Kumar, L. Obulapathi, T. Sofi Sarmash, K. Chandra Babu Naidu, D. Jhansi Rani, T. Subba Rao, Digest Journal of Nano materials and Biostructures 10 (2015) 155-159

[14] M. Maddaiah, K. Chandra Babu Naidu, D. Jhansi Rani, T. Subbarao, Journal of Ovonic Research 11 (2015) 99-106

[15] M.R. Bhandare, H.V. Jamadar, A.T. Pathan, B.K. Chougule, A.M. Shaikh, Journal of Alloys and Compounds 509 (2011) L113-L118

[16] K. Chandra Babu Naidu, T. Sofi Sarmash, M. Maddaiah, V. Narasimha Reddy and T. Subbarao, AIP Conference Proceedings 1665 (2015) 040001; doi: 10.1063/1.4917614

[17] K. C. Babu Naidu, T. Sofi Sarmash, M. Maddaiah, A. Gurusampath Kumar, D. Jhansi Rani, V. Sharon Samyuktha, L. Obulapathi, T. Subbarao, Journal of Ovonic Research 11 (2015) 79-84

[18] D. Kothandan, R. Jeevan Kumar, Journal of The Australian Ceramic Society 52 (2016) 156-166

[19] S. Anil Kumar, K. Chandra Babu Naidu, International Journal of ChemTech Research 9(1) (2016) 58-63

[20] S. Prathap, K. Chandra Babu Naidu, and W. Madhuri, AIP Conference Proceedings 1731 (2016) 030019; doi: 10.1063/1.4947624015

[21] R. Manjula, V.R.K. Murthy, J. Sobhanadri, Journal of Applied Physics 59 (1986) 2929-2931

[22] R. Islam, M.A. Hakim, M.O. Rahman, H. Narayan Das, M.A. Mamun, Journal of Alloys and Compounds 559 (2013) 174-180

Cite the paper

K.T. Veeranjaneaya, D. Ravinder (2017). *Electrical Properties of Ni0.4Mgo0.6Fe2O4 Synthesized by Conventional Solid-State Reaction Method*. Mechanics, Materials Science & Engineering, Vol 9. DOI: 10.2412/mmse.28.98.879