Journal ArticleDOI
Temperature-dependent magnetization, anisotropy and conductivity of CoFe 2-x Sn x O 4 (x = 0.025, 0.05, 0.075): appearance of grain boundary conductivity at high temperatures
Kodam Ugendar,V. Vaithyanathan,L. N. Patro,S.S.R. Inbanathan,K. Kamala Bharathi,K. Kamala Bharathi +5 more
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In this paper, the temperature dependence of magnetization, anisotropy, ac and dc conductivity of CoFe2?x Sn x O4 (x??=??0.05, 0.075) were investigated and the results are reported.Abstract:
The temperature dependence of magnetization, anisotropy, ac and dc conductivity of CoFe2?x Sn x O4 (x??=??0.025, 0.05, 0.075) were investigated and the results are reported. All the compounds were prepared by a solid-state reaction, and the formation of the compounds in the cubic inverse spinel phase was confirmed from their Rietveld refined x-ray diffraction (XRD) patterns and Raman spectra. Increments in the lattice constant were observed upon the partial substitution of Fe3+ by Sn4+. The presence of all elements and their ionic states were confirmed from x-ray photoelectron spectroscopic studies. Magnetic hysteresis loops were measured for each compound at temperature 20?K and 50?300?K (in steps of 50?K) using a superconducting quantum interference device vibrating sample magnetometer. Both magnetization and magnetic anisotropy showed a decrease in values with increasing Sn substitution. Room temperature (RT) magnetization is seen to decrease from 80?65.91 emu g?1 with increasing Sn concentration from x??=??0 (CoFe2O4) to 0.075 (CoFe1.925Sn0.075O4). The high field regimes of the hysteresis loops were modeled using the law of approach to the saturation magnetization equation. The temperature variation of magnetization and magnetic anisotropy are explained on the basis of a one-ion model. Complex impedance spectroscopy studies at RT show that the conductivity in these materials is predominantly due to the intrinsic bulk grains. With increasing the temperature, evolution of the grain boundary conduction is clearly seen through the appearance of a second semi-circle in the complex impedance plots. The RT total dc conductivity value of CoFe2?x Sn x O4 (x??=??0, 0.025, 0.05, 0.075) is found to be 5.78??×??10?8, 8.56??×??10?8, 1.44??×??10?7 and 1.11??×??10?7 S cm?1 respectively. The observation of well-distinguishable grain and grain boundary conductions and the low conductivity values in the CoFe2?x Sn x O4 (x??=??0, 0.025) materials indicates that these materials are promising candidates for high-frequency applications.read more
Citations
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Tuning of the magnetostrictive properties of cobalt ferrite by forced distribution of substituted divalent metal ions at different crystallographic sites
P.N. Anantharamaiah,P. A. Joy +1 more
TL;DR: In this paper, the role of the substituted non-magnetic divalent metal ions in the magnetostrictive properties of cobalt ferrite has been investigated by substitution of Zn2+ and/or Mg2+ for Fe3+ in CoMgxFe2−xO4.
Journal ArticleDOI
Influence of Mn dopant on the crystallite size, optical and magnetic behaviour of CoFe2O4 magnetic nanoparticles
TL;DR: In this paper, a chemical precipitation method was used to synthesize cobalt ferrite nanoparticles with size of 38-72nm by using a single domain spinel structure, which is a direct bandgap material with bandgap ranges from 3.84 to 4.02 eV.
Journal ArticleDOI
Progress in multiferroic and magnetoelectric materials: applications, opportunities and challenges
TL;DR: In this article, a review of MFs and magnetoelectric materials using a multidisciplinary approach to address the underlying mechanism responsible for the coupling, their applications in some novel devices, new opportunities and future challenges is presented.
Journal ArticleDOI
Ferro to superparamagnetic transition: Outcome of Ni doping in polyethylene glycol capped CoFe2O4 nanoparticles
TL;DR: In this paper, Nanocrystalline CoFe2O4 and Ni doped CoFe 2O4 were synthesized via chemical precipitation method and their crystal structure, energy gap and magnetic properties were investigated at room temperature.
Journal ArticleDOI
Augmenting the catalytic performance of spinel nanoferrites (CoFe2O4 and NiFe2O4) via incorporation of Al into the lattice
Ankita Goyal,Surendra Kumar Bansal,Bhupendra Chudasama,Kulbhushan Tikoo,Vinod Kumar,Sonal Singhal +5 more
TL;DR: In this paper, Al has been incorporated into the lattice of spinel nanoferrites and the effect of increasing Al content on the catalytic performance is thought to be related to synergistic interactions among the metal ions present in the surface-exposed octahedral sites.
References
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