Structural and Magnetization Behaviors of Ni Substituted Li-Mg Ferrites

M. Mahbubur Rahman, Banalota Moonmoon Sonia, Mithun Kumar Das, Farid Ahmed, Md. Abul Hossain, D. K. Saha, Shireen Akhter

  Open Access OPEN ACCESS  Peer Reviewed PEER-REVIEWED

Structural and Magnetization Behaviors of Ni Substituted Li-Mg Ferrites

M. Mahbubur Rahman1, 2,, Banalota Moonmoon Sonia1, Mithun Kumar Das1, Farid Ahmed1, Md. Abul Hossain1, D. K. Saha3, Shireen Akhter3

1Department of Physics, Jahangirnagar University, Savar, Dhaka, Bangladesh

2School of Engineering & Information Technology, Murdoch University, Perth, Western Australia, Australia

3Materials Science Division, Atomic Energy Centre, Ramna, Dhaka, Bangladesh

Abstract

Magnetization behaviors of Ni-substituted LixMg0.5Ni0.5-2xFe2+xO4 ferrites, where x = 0.25, 0.20, 0.15, 0.10 and 0.00 synthesized by standard ceramic technology sintered at 1300°C in air for 5 hours has been presented in the present study. The bulk density and lattice constants of the samples found to be decreased with the increase in the Ni-content for the x values from 0.25 to 0.00. DC electrical resistivity has found to show highest magnitude at room temperature and decreases with further increase in temperature. Magnetization of the samples has been measured as a function of the field using hysteresis loop tracer at 30°C. It was observed that addition of nickel in polycrystalline Li-Mg ferrites plays an important role in modification of structural and magnetization characteristics.

At a glance: Figures

Cite this article:

  • Rahman, M. Mahbubur, et al. "Structural and Magnetization Behaviors of Ni Substituted Li-Mg Ferrites." International Journal of Physics 1.5 (2013): 128-132.
  • Rahman, M. M. , Sonia, B. M. , Das, M. K. , Ahmed, F. , Hossain, M. A. , Saha, D. K. , & Akhter, S. (2013). Structural and Magnetization Behaviors of Ni Substituted Li-Mg Ferrites. International Journal of Physics, 1(5), 128-132.
  • Rahman, M. Mahbubur, Banalota Moonmoon Sonia, Mithun Kumar Das, Farid Ahmed, Md. Abul Hossain, D. K. Saha, and Shireen Akhter. "Structural and Magnetization Behaviors of Ni Substituted Li-Mg Ferrites." International Journal of Physics 1, no. 5 (2013): 128-132.

Import into BibTeX Import into EndNote Import into RefMan Import into RefWorks

1. Introduction

Properties like high permeability, low loss feature, high stability of permeability with temperature and time, high wear resistance, controlled coercive force, low switching coefficient etc. have appositely placed Li-Mg ferrites as highly demandable ferrites to both researchers and manufacturers [1]. Li-ferrites became commercially important as computer memory core materials in the early 1960’s. The high Curie temperature, leading to unparallel thermal stability and high saturation magnetization all prompted this commercial interest. For many of the same reasons, there was considerable development effort aimed at providing microwave quality Li-ferrites [2, 3, 4, 5]. The principal interest in microwave Li-ferrites is a low cost replacement for the rare-earth iron garnets, offering improved temperature performance. Li-ferrites with magnetizations comparable to the garnets are very refractory due to the high concentration and nature of the substitution elements, which requires relatively high sintering temperatures. This type of heat treatment causes the volatility of Li2O [6] which results in reduction of iron. For this reason, Li-ferrites were considered difficult to prepare with magnetization characterized by high porosities. As a result, high coercive forces and broad resonance line-widths were experienced [7]. The properties of Li-Ni ferrites studied by Bhatu et al. [8] reported an increase in magnitude of elastic constants, elastic wave velocities and infrared spectral analysis is found easier, valid and suitable for spinel ferrite. The Magnetic studies of Co-substituted Li-Zn ferrites in Ref. [9] reported that cobalt shows anomalous behavior when substituted in Li-ferrites in the presence of Zn [10]. Structural and magnetic properties of Mg-doped Li0.41Fe2.41Mg0.17O4 ferrites were investigated by Widatallah et al. [11] while the Fe doped NiO ferrites have been reported in Ref. [12]. More recently magnetic, dielectric and electrical properties of La2O3 and simultaneous addition of 1 wt% (CaO + SiO2) doped Ba-hexaferrites has been studied [13].

Over the years, it has been observed that pure and mixed Li-ferrites are highly potential candidates for microwave applications, especially as replacements for garnets, due to their low cost. The squareness of the hysteresis loop and superior temperature performance are other application in microwave devices [7, 8]. Effect of various substitutions in Li-ferrites exhibit very good relaxation and anisotropy properties than other type of ferrites [9, 10]. Studies of Li-Mg-Fe spinels show that it can be useful in microwave applications with improved magnetic properties [11, 14]. Besides pure Li, Li-Mg and Li-Ni ferrites [6, 7, 8], many researchers have extensively studied Li-Zn [15, 16], Li-Co [17], Li-Cd [18] and Li-Cr [19] ferrites. However, reports on the magnetization behaviors of nickel substituted Li-Mg ferrites are still very little. In view of the great interest of Li-Mg ferrites, both for their technological applications and theoretical understanding of the mechanisms involved, the present work is aimed at finding the effect of Ni-addition on the structural and magnetization behaviors of Li-Mg ferrites.

2. Materials and Method

Ni-substituted LixMg0.5Ni0.5-2xFe2+xO4 polycrystalline ferrites, where x=0.25, 0.20, 0.15, 0.10 and 0.00 were prepared by conventional ceramic technique. The high purity level analytical grade chemical ingredients of NiO (99.9%), MgO (99.9%), Li2CO3 (99+%), Fe2O3 (99.9%) have been as supplied by the manufacturer. All the raw materials were mixed thoroughly with stainless steel balls in a ball-milling machine with distilled water as fluid. The presintering of the samples was carried out at 900°C for 5 hours in air atmosphere. The presintered samples were milled and pressed at 2 tons pressure into disk shape of 10 mm diameter. A small quantity of polyvinyl alcohol was added as binding material to the powder. The final sintering of the end products was done at 1300°C for 5 hours in air. Elaborate explanations about the specimen preparation technique are available in the literature [13, 20, 21, 22, 23, 24, 25, 26, 27]. The hysteresis loop measurements of the samples was performed by Automatic Magnetic Hysteresisgraph (Model: HYSTERGRAF IS-300 of Laboratorio Elettrofisico Engineering SRL, Italy) installed at the Materials Science Division, Atomic Energy Centre, Dhaka, Bangladesh. The magnetization versus applied magnetic field measurement has been performed by the Vibrating Sample Magnetometer (VSM), Model: EV9 of Micro Sense, USA at the Materials Science Division, Atomic Energy Centre, Dhaka, Bangladesh. The measurement has been performed by varying the applied magnetic field from -1 to + 1 kOe. The weight of each sample was approximately 20 mg. The saturation magnetization has been derived from the VSM measurements. Magnetic parameters e.g., coercive field, remnant magnetization, magnetization at the maximum field, etc can be determined from hysteresis loops.

3.Results and Discussion

3.1. Structural Properties of Li-Mg Ferrites

The structural characterization and phase identification of the samples have been done byX-ray diffraction (XRD) technique using Philips X’PERT PRO X-ray diffractometer using Cu-Kα radiation in the 2θ = 20° to 80° geometry in steps of 0.02°. XRD patterns confirmed the single-phase cubic spinel structure of ferrites without having any other intermediate phases. Well-defined diffraction lines along with the crystallization phase also confirm the high purity level of the ferrite powders. XRD data of such measurements have been presented in our earlier publication [26]. The structural characterizations of Li-Mg ferrites have been performed measuring the bulk density, theoretical density, lattice parameters and porosity of the samples. Working principle for the theoretical density, lattice parameters and porosity are given in Ref. [26]. Bulk density and theoretical density of the samples have been presented in Figure 1. According to the data shown in Figure 1, it has been observed that the density of the samples with and without additives observed to vary between 4.47 gm/cc and 4.21 gm/cc. With the increase in Ni-content the the bulk density of Li-Mg ferrite was decreased up to 4.21 gm/cc while the theoretical density has been found to reduce from 5.051 to 4.924 g/cc. The lattice parameters of the Li-Mg ferrites have been found to be decreased with the progressive addition of the nickel content to the pure samples which has been shown in Figure 2. This variation in lattice parameters is well known to obey the Vegard’s law [28]. These new measurements for the samples sintered at 1300°C have been found to be consistent with our earlier study for Li-Mg-Ni ferrites sintered at 1200°C [26]. The decrease in these parameters may be related to the replacement of Li2+ ion with larger ionic radius (0.88 Å) by Ni2+ ion with smaller ionic radius (0.72 Å). The difference in the lattice parameter may also be explained by the cation migration since Ni2+ ions on the A-sites exhibit a smaller ionic radius than on the B-sites because of covalence effects [29]. The remarkable effect is the anomaly shift, due to the redistribution of cations. This behavior is appeared clearly in the physical properties such as density, porosity and magnetic properties. Figure 3 shows that the porosity of Li-Mg ferrites has been found to be increased with the increase in Ni-content to the Li-Mg ferrites. This confirms the fact that the nickel possesses the higher atomic weight than that of lithium and iron. It is also believed that the replacement of Mg2+ ion with smaller ionic radius (0.75 Å) by Ni2+ ion with larger ionic radius (0.77 Å) may be responsible for the increase in porosity with the increase in Ni-content. Elaborate explanations about the variation in bulk density, theoretical density, lattice parameters and porosity is available in Ref. [26].

Figure 1. Bulk density and theoretical density of LixMg0.5Ni0.5-2xFe2+xO4 ferrites sintered at 1300°C in air for 5 hours
Figure 2. Lattice parameters of LixMg0.5Ni0.5-2xFe2+xO4 ferrites sintered at 1300°C in air for 5 hours
Figure 3. Porosity of LixMg0.5Ni0.5-2xFe2+xO4 ferrites sintered at 1300°C in air for 5 hours
3.2. DC Resistivity of Li-Mg Ferrites

Figure 4 shows the DC electrical resistivity at room temperature of Li-Mg ferrites sintered at 1300 ºC in air for 5 hours. From the resistivity data, it is clear that the room temperature DC resistivity of Li-Mg ferrites increases linearly with the increase in Ni-content. DC resistivity data has been found to be consistent with the porosity data (Figure 3) reveals the fact that the rise in resistivity with the increase in Ni-content to the Li-Mg ferrites attributed to the porous nature of this ferrite [30]. It is also believed that a controlled amount of Ni is added to the undoped sample the resistivity because Ni acts as a dead layer over the surface of the Li-Mg ferrites thus reducing the conductivity. It is well established that the electrical conductivity is basically responsible for the exchange of electrons between Fe2+ and Fe3+ [13, 22, 23, 24, 26, 27]. The electronic exchange between Fe2+ and Fe3+ might results in the local displacement of charges and thereby polarization takes place in the ferrites. The magnitude of electronic exchange is dependent on the concentration of the ‘Fe3+/ Fe2+ ion pairs present on the octahedral B-sites. In ferrites system, the concentration of Fe2+ ion depends upon the sintering atmosphere, sintering time and temperature, annealing time and so on. Microstructure of ferrites also play significant role in controlling the electrical resistivity of ferrites as reported in Refs. [31, 32, 33].

Figure 4. Variation of room temperature resistivity of Li-Mg ferrites sintered at 1300º C in air for 6 hours with content x
Figure 5. Hysteresis loop for sample LixMg0.5Ni0.5-2xO4 for x = 0.00, 0.10, 0.15, 0.20 and 0.25
Figure 6. Variation of coercive force of LixMg0.5Ni0.5-2xO4 for x= 0.00, 0.10, 0.15, 0.20 and 0.25
3.3. Magnetization Behaviors of Li-Mg Ferrites

The lag or delay of a magnetic materials is commonly termed as magnetic hysteresis, relates to the magnetization properties of a material by which it firstly becomes magnetized and then demagnetized. Hysteresis measurements of Li-Mg ferrites with compositions LixMg0.5Ni0.5-2xO4 where x = 0.0, 0.10, 0.15, 0.20, 0.25 were performed by an Automatic Magnetic Hysteresisgraph for a magnetic field ranging from -1000 Oe to + 1000 Oe are shown in Figure 5. The magnetization of the sample increases linearly with increase in applied magnetic field and then saturation occurs. Using the hysteresis loop presented in Figure 5, the hysteresis parameters viz., saturation magnetization (Ms), coercivity (Hc), remanent induction (Br) are estimated and presented in Figure 6, Figure 7 and Figure 8. Firstly, with the small introduction of Ni-content the coercivity of the Li-Mg ferrites has been found to be increased and then decreased and increased again with further increase in nickel content as is observed in Figure 6. It is apparent that the softness of Li-Mg ferrites is decreased by the addition of Ni as the remanent induction is increased shown in Figure 7. For x = 0.00 the loop tells us that Li-Mg ferrites is a very soft magnet to devise as the remanence and coercive forces both are least. The saturation magnetization of Li-Mg ferrites increases first with the introduction of Ni ions then decreases with the increase in Ni-content for x = 0.15 and then increases linearly with the further increase in nickel content which has been shown in Figure 8. The decrease in saturation magnetization is due to the increase in magnetic dilution of A–B interaction. Since, the Mg2+ ions are the same in all the samples, we believe they will not affect the magnetization behavior of our samples. The Li1+ ion is nonmagnetic which also does not responsible to the magnetization of the sub-lattice and hence might not impart to the net magnetic moment. Thus, the magnetization behaviour of the ferrite samples arises mainly due to the contributions of the magnetic moments from Fe3+ and Ni2+ at B-sites [34]. At B-sites, Ni2+ ions replace the Fe3+ ions and nonmagnetic Li1+ ions. Neel’s phenomenological model can be successfully applied to explain the increase of saturation magnetization in Li-Mg ferrites with nickel substitution. Neel’s model states that the A–B super-exchange interaction is stronger than that of A–A and B–B exchange interaction. The saturation magnetization is given by the vector sum of the magnetic moments of the individual A and B sub-lattices. The decrease of magnetization may be due to the fact that the magnetization of A-sublattice becomes much diluted that the A-B exchange interaction becomes weaker or comparable with the B-B exchange interactions [21]. This gives rise to the canted spins. The existence of canted spin gives rise to Yafet-Kittel (Y-K) angle which compares the strength of A-B and B-B exchange interaction. The decrease of magnetization can be also treated theoretically by triangular arrangement of spins as proposed by Yafet and Kittel according to Ref. [35]. The moderate saturation magnetization values of Li-Mg ferrites with nickel substitution find their potential applications in the high frequency devices [36]. The changes in saturation magnetization, coercivity, and remanence are not linear because of the refractory property of nickel hinders to grain growth as well as the other magnetic properties.

Figure 7. Variation of remanence of LixMg0.5Ni0.5-2xO4 for x = 0.00, 0.10, 0.15, 0.20 and 0.25
Figure 8. Variation of saturation magnetization of LixMg0.5Ni0.5-2xO4 for x = 0.00, 0.10, 0.15, 0.20 and 0.25

4. Conclusions

Structural and magnetization characteristics of polycrystalline Li-Mg ferrites have been reported with the addition of Ni-content by replacing Li-content. Throughout the study, it has been noticed that the structural properties of Li-Mg ferrites are improved remarkably with the addition of Ni-content. According to the DC resistivity measurements, it has been observed that at room temperature resistivity is maximum and decreases with increasing temperature. The decrease of magnetization with the introduction of nickel to the pure Li-Mg ferrites might be associated with the refractory behavior of nickel ions. The weakening of the super exchange interaction due to magnetic dilution and disruptions of the collinear spin structure have also found to be responsible for the modification of the magnetization behaviors of the Li-Mg ferrites with the progressive addition of nickel content.

References

[1]  I. Soibam, S. Phanjoubam, H.B. Sharma, H.N.K. Sarma, C. Prakash, Preparation and studies of electrical properties of cobalt substituted Li-Zn ferrites by sol-gel auto combustion method, Indian J. Phys., 83, 285 (2009). doi: 10.1007/s12648-009-0123-y
In article      CrossRef
 
[2]  W. Schiessl, W. Potzel, H. Karzel, M. Steiner, G. M Kalvius, Magnetic properties of the ZnFe2O4 spinel, Phys. Rev., B, 53, 9143 (1996). doi: 10.1103/PhysRevB.53.9143
In article      CrossRef
 
[3]  J.M. Hasting, L.M. Corliss, An antiferromagnetic transition in zinck ferrite, Phys. Rev. B, 102, 1460 (1956). doi: 10.1103/PhysRev.102.1460
In article      CrossRef
 
[4]  J.M. Hasting L.M. Corliss, Review of Modern Physics, 25, 114 (1953). doi: 10.1103/RevModPhys.25.114
In article      CrossRef
 
[5]  Y.G. Chukalkin, A.E. Teplykh, Magnetic state of nickel-zinc ferrites at high zinc concentrations, Physics of the Solid State, 40, 1364 (1998). doi: 10.1134/1.1130559
In article      CrossRef
 
[6]  M.A. Ahmed, N. Okasha, L. Salah, Influence of yttrium ions on the magnetic properties of Ni–Zn ferrites, J. Magn. Magn. Mater., 264, 241 (2003). doi: 10.1016/S0304-8853(03)00212-9
In article      CrossRef
 
[7]  G.O. White, C.E. Patton, Magnetic properties of lithium ferrite microwave materials, J. Magn. Magn. Mater., 9, 299 (1978). doi: 10.1016/0304-8853(78)90085-9
In article      CrossRef
 
[8]  S.S. Bhatu, Lakhani, V.K., Tanna, A. R., Vasoya, N.H., Buch, J.U., Sharma, P.U. Trivedi, U.N., Joshi, H,H., Modi, K.B., Effect of nickel substitution on structural, infrared and elastic properties of lithium ferrite, Indian J. Pure & Appl. Phys., 45, 597 (2007).
In article      
 
[9]  I. Soibam, S. Phanjoubam, C. Prakash, Magnetic and Mössbauer studies of Ni substituted Li–Zn ferrite, J. Magn. Magn. Mater., 321, 2779 (2009). doi: 10.1016/j.jmmm.2009.04.011
In article      CrossRef
 
[10]  C.J. Brower, C.E. Patton, Determination of anisotropy field in polycrystalline lithium ferrites from FMR linewidths, J. Appl. Phys., 53, 2104 (1982). doi: 10.1063/1.330712
In article      CrossRef
 
[11]  H.M. Widatallah, C. Johnson, A.M. Gismelseed, I.A. Al-Omari, S.J. Stewart, S.H. Al-Harthi, S. Thomas, H. Sitepu, Structural and magnetic studies of nanocrystalline Mg-doped Li0. 5Fe2. 5O4 particles prepared by mechanical milling, J. Phys. D: Appl. Phys., 41, 165006 (2008). doi: 10.1088/0022-3727/41/16/165006
In article      CrossRef
 
[12]  P. Mallick, C. Rath, R. Biswal, N.C. Mishra, Structural and magnetic properties of Fe doped NiO, Indian J. Phys., 83, 517 (2009). doi: 10.1007/s12648-009-0012-4
In article      CrossRef
 
[13]  S. Pervin, M.M. Rahman, F. Ahmed, M.A. Hakim, Investigation of magnetic, dielectric and electrical properties of Ba-hexaferrites, Indian J. Phys., 86 (12), 1065 (2012).
In article      
 
[14]  C.E. Patton, C.A. Edmonson, Y.H. Liu, Magnetic properties of lithium zinc ferrite, J. Appl. Phys., 53, 2431 (1982). doi: 10.1063/1.330835
In article      CrossRef
 
[15]  A.M. Abo El Ata, S.M. Attia, D.E. Kony, A.H. Al-Hammadi, Spectral, initial magnetic permeability and transport studies of Li0.5−0.5xCoxFe2.5−0.5xO4 spinel ferrite, J. Magn. Magn. Mater., 295, 28 (2005). doi: 10.1016/j.jmmm.2004.12.035
In article      CrossRef
 
[16]  S.S. Bellad, S.C. Warawe, A.M. Shabardin, B.K. Chougule, Bull. Mater. Sci., 23, 83 (2000). doi: 10.1007/BF02706546
In article      CrossRef
 
[17]  R. Laishram, C. Prakash, Magnetic properties of Cr3+ substituted Li–Sb ferrites, J. Magn. Magn. Mater, 305, 35 (2006). doi: 10.1016/j.jmmm.2005.11.037
In article      CrossRef
 
[18]  S.S. Bellad, R.B. Pujar, B.K. Chougule, Structural and magnetic properties of some mixed Li-Cd ferrites, Mater. Chem. Phys., 52(2), 166 (1998). doi: 10.1016/S0254-0584(98)80019-9
In article      CrossRef
 
[19]  A. Goldman, Handbook of Mod. Ferro. Mat. (Kulwer Academy), 98 (1999).
In article      
 
[20]  Z.H. Khan, M. Mahbubur Rahman, S.S. Sikder, M.A. Hakim, D.K. Saha, Complex Permeability in Iron Deficient Ni-Cu-Zn Ferrites, J. Alloys Comp., 548, 208 (2013). doi: 10.1016/j.jallcom.2012.09.037
In article      CrossRef
 
[21]  Sumon Kumar Nath, M. Mahbubur Rahman, S.S. Sikder, M.A. Hakim, Magnetization and Magnetic Behavior of Ni1-xCdxFe2O4 Ferrites, ARPN Journal of Science & Technology, 3(1), 106 (2013).
In article      
 
[22]  Nipa Debnath, M. Mahbubur Rahman, Farid Ahmed, M.A. Hakim, Study of the Effect of Rare Earth Oxide Addition on the Magnetic and Dielectric Properties of Sr-Hexaferrites, International Journal of Engineering & Technology, 12 (5), 49 (2012).
In article      
 
[23]  Nipa Debnath, M. Mahbubur Rahman, Farid Ahmed, M.A. Hakim, Magnetic and Dielectric Properties of M-Type Sr-Hexaferrites with the Addition of Calcium Oxide and Silicon-di-Oxide, Journal of Advanced Physics, 1 (2), 136 (2012). doi: 10.1166/jap.2012.1034
In article      CrossRef
 
[24]  M. Mahbubur Rahman, Prashanta Kumar Halder, Farid Ahmed, Mashudur Rahaman, Tofazzal Hossain, Effect of Ca-substitution on the Magnetic and Dielectric Properties of Mn-Zn Ferrites, Journal of Scientific Research, 4 (2), 297 (2012).
In article      
 
[25]  Z.H. Khan, M. Mahbubur Rahman, S.S. Sikder, M.A. Hakim, Shireen Akhter, H.N. Das, B. Anjuman, Thermal Hysteresis of Permeability and Transport Properties of Cu Substituted Ni0.28Cu0.10+xZn0.62-xFe1.98O4 Ferrites, Advanced Chemistry Letters, 1 (2), 111 (2013). doi: 10.1166/acl.2013.1016
In article      CrossRef
 
[26]  Mithun Kumar Das, M. Mahbubur Rahman, Banalota Moonmoon Sonia, Farid Ahmed, Md. Abul Hossain, Mashudur Rahaman, M. Shahriar Bashar, Tofazzal Hossain, D.K. Saha, Shireen Akhter, Magnetic, Dielectric and Electrical Properties of Lithium-Magnesium Ferrites, Advanced Chemistry Letters, 1 (2), 104 (2013).
In article      
 
[27]  M. Mahbubur Rahman, Md. Shahin Sheakh, Sohely Pervin, Nasir Uddin, Farid Ahmed, Md. Abul Hossain, Mashudur Rahaman, M. Shahriar Bashar, Tofazzal Hossain, Shireen Akhter, Composition, Temperature and Frequency Dependent Magnetic, Dielectric and Electrical Properties of Magnesium-Zinc Ferrites, Journal of Bangladesh Academy Sciences, 36 (2), 199 (2012).
In article      
 
[28]  L. Vegard, Z. Phys., 5 (1), 17 (1921). doi: 10.1007/BF01349680
In article      CrossRef
 
[29]  G. Blasse, Philips Res. Suppl. B., 3, 91 (1964).
In article      
 
[30]  S.C. Watawe, B.D. Sarwade, S.S. Bellad, B.D. Sutar, B.K. Chougule, Microstructure, frequency and temperature-dependent dielectric properties of cobalt-substituted lithium ferrites, J. Magn. Magn. Mater., 214, 55 (2000). doi: 10.1016/S0304-8853(00)00033-0
In article      CrossRef
 
[31]  K.W. Long, S.C. Chung Wei, J. Phys. D (GB), 13/2, D-259 (1980).
In article      
 
[32]  A.B. Naik, J.I. Powar, Dependence of resistivity and activation energy of Ni-Zn ferrites on sintering temperature and porosity, Indian J. Pure Appl. Phys., 23, 436 (1985).
In article      
 
[33]  O.S. Josyulu, J. Sobhanadri, Phys. Stat. Sol. A, 59, 323 (1980). doi: 10.1002/pssa.2210590143
In article      CrossRef
 
[34]  A.K.M. Akther Hossain, M.A. Rahman, S.F.U. Farhad, B. Vilquin, H. Tanaka, Effect of Li substitution on the magnetic properties of LixMg0.40Ni0.60−2xFe2+xO4 ferrites, Physica B: Conden. Matt., 406, 1506 (2011). doi: 10.1016/j.physb.2011.01.058
In article      CrossRef
 
[35]  Y. Yafet, C. Kittel, Phys. Rev., 87 (1952) 239. doi: 10.1103/PhysRev.87.290
In article      CrossRef
 
[36]  S.S. Bellad, B.K. Chougule, Composition and frequency dependent dielectric properties of Li–Mg–Ti ferrites, Mater. Chem. Phys., 66, 58 (2000). doi: 10.1016/S0254-0584(00)00273-X
In article      CrossRef
 
  • CiteULikeCiteULike
  • Digg ThisDigg
  • MendeleyMendeley
  • RedditReddit
  • Google+Google+
  • StumbleUponStumbleUpon
  • Add to DeliciousDelicious
  • FacebookFacebook
  • TwitterTwitter
  • LinkedInLinkedIn