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Proceedings ArticleDOI

Dielectric response of the magnetic perovskite oxide Eu2FeCoO6

10 Apr 2018-Vol. 1942, Iss: 1, pp 130052
TL;DR: In this article, the authors presented the dielectric response of the magnetic perovskite Eu2FeCoO6 from impedance spectroscopy measurements and inferred the two-step relaxation process from Arrhenius fit.
Abstract: The rare earth based transition metal perovskites are well known for their tunable physical properties. Here we present the dielectric response of the magnetic perovskite Eu2FeCoO6 from impedance spectroscopy measurements. The compound having a weak ferromagnetic ground state, is subjected to impedance spectroscopy measurements through the frequency range 100 Hz to 10 MHz for the temperature range 123 K-473 K. The dielectric permittivity shows huge values at high temperatures with low frequency. The two step relaxation process is inferred from Arrhenius fit.The rare earth based transition metal perovskites are well known for their tunable physical properties. Here we present the dielectric response of the magnetic perovskite Eu2FeCoO6 from impedance spectroscopy measurements. The compound having a weak ferromagnetic ground state, is subjected to impedance spectroscopy measurements through the frequency range 100 Hz to 10 MHz for the temperature range 123 K-473 K. The dielectric permittivity shows huge values at high temperatures with low frequency. The two step relaxation process is inferred from Arrhenius fit.
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Journal ArticleDOI
TL;DR: Evidence is provided for the tuning of magnetoelectric coupling by rare-earth substitution in this family of oxides by seeing that electric polarization is seen to get enhanced as a result of rare- earth substitution with respect to that in DyFe0.5Cr 0.5O3.
Abstract: We report the results of our investigations on the influence of partial substitution of Er and Gd for Dy on the magnetic and magnetoelectric properties of DyFe0.5Cr0.5O3, which is known to be a multiferroic system. Magnetic susceptibility and heat capacity data, apart from confirming the occurrence of magnetic transitions at ~ 121 and 13 K in DyFe0.5Cr0.5O3, bring out that the lower transition temperature only is suppressed by rare-earth substitution. Multiferroic behavior is found to persist in Dy0.4Ln0.6Fe0.5Cr0.5O3 (Ln= Er and Gd). There is an evidence for magnetoelectric coupling in all these materials with qualitative differences in its behavior as the temperature is changed across these two transitions. Remnant electric polarization is observed for all the compounds. The most notable observation is that electric polarization is seen to get enhanced as a result of rare-earth substitution with respect to that in DyFe0.5Cr0.5O3. Interestingly, similar trend is seen in magnetocaloric effect, consistent with the existence of magnetoelectric coupling. The results thus provide evidence for the tuning of magnetoelectric coupling by rare-earth substitution in this family of oxides.

16 citations

Journal ArticleDOI
TL;DR: The abundance and the versatility of the cellulose structure based on the route of modification have attracted many researchers in the scientific community as discussed by the authors, and they can be taken from many natural...
Abstract: The abundance and the versatility of the cellulose structure based on the route of modification have attracted many researchers in the scientific community. Cellulose can be taken from many natural...
References
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Journal ArticleDOI
17 Aug 2006-Nature
TL;DR: A ferroelectric crystal exhibits a stable and switchable electrical polarization that is manifested in the form of cooperative atomic displacements that arises through the quantum mechanical phenomenon of exchange.
Abstract: A ferroelectric crystal exhibits a stable and switchable electrical polarization that is manifested in the form of cooperative atomic displacements. A ferromagnetic crystal exhibits a stable and switchable magnetization that arises through the quantum mechanical phenomenon of exchange. There are very few 'multiferroic' materials that exhibit both of these properties, but the 'magnetoelectric' coupling of magnetic and electrical properties is a more general and widespread phenomenon. Although work in this area can be traced back to pioneering research in the 1950s and 1960s, there has been a recent resurgence of interest driven by long-term technological aspirations.

6,813 citations

Journal ArticleDOI
TL;DR: It is found that even a weak magnetoelectric interaction can lead to spectacular cross-coupling effects when it induces electric polarization in a magnetically ordered state.
Abstract: Magnetism and ferroelectricity are essential to many forms of current technology, and the quest for multiferroic materials, where these two phenomena are intimately coupled, is of great technological and fundamental importance. Ferroelectricity and magnetism tend to be mutually exclusive and interact weakly with each other when they coexist. The exciting new development is the discovery that even a weak magnetoelectric interaction can lead to spectacular cross-coupling effects when it induces electric polarization in a magnetically ordered state. Such magnetic ferroelectricity, showing an unprecedented sensitivity to ap plied magnetic fields, occurs in 'frustrated magnets' with competing interactions between spins and complex magnetic orders. We summarize key experimental findings and the current theoretical understanding of these phenomena, which have great potential for tuneable multifunctional devices.

3,683 citations

Journal ArticleDOI
TL;DR: The results suggest that the alkaline-earth hydrides form an important new family of materials, with potential use in a number of applications, such as separation membranes, electrochemical reactors and so on.
Abstract: With hydrogen being seen as a key renewable energy vector, the search for materials exhibiting fast hydrogen transport becomes ever more important. Not only do hydrogen storage materials require high mobility of hydrogen in the solid state, but the efficiency of electrochemical devices is also largely determined by fast ionic transport. Although the heavy alkaline-earth hydrides are of limited interest for their hydrogen storage potential, owing to low gravimetric densities, their ionic nature may prove useful in new electrochemical applications, especially as an ionically conducting electrolyte material. Here we show that barium hydride shows fast pure ionic transport of hydride ions (H(-)) in the high-temperature, high-symmetry phase. Although some conductivity studies have been reported on related materials previously, the nature of the charge carriers has not been determined. BaH2 gives rise to hydride ion conductivity of 0.2 S cm(-1) at 630 °C. This is an order of magnitude larger than that of state-of-the-art proton-conducting perovskites or oxide ion conductors at this temperature. These results suggest that the alkaline-earth hydrides form an important new family of materials, with potential use in a number of applications, such as separation membranes, electrochemical reactors and so on.

86 citations

Journal ArticleDOI
TL;DR: In this paper, structural, magnetic, and dielectric properties of RFe0.5Cr 0.5O3 compounds have been investigated and it has been shown that the competition between the moments of the two clusters gives rise to the R-dependent temperature induced magnetization reversal.
Abstract: We have investigated the structural, magnetic, and dielectric properties of RFe0.5Cr0.5O3 (R = Nd, Sm, Gd, and Y) compounds. Both structure and magnetic analyses show a Fe/Cr cation disorder, which results in the existence of Fe-rich and Cr-rich clusters. The competition between the moments of the two clusters gives rise to the R-dependent temperature induced magnetization reversal. Interestingly, we also find that the charge carrier hopping in the two clusters leads to two sequential dielectric relaxations in all the samples. In addition, giant magnetocaloric effect with a magnetic entropy change reaching ∼29.2 J/kg K was observed with R = Gd.

39 citations

Journal ArticleDOI
TL;DR: In this article, the influence of rare-earth substitution on the magnetic and magnetoelectric properties of DyFe0.5Cr 0.5O3 was investigated and it was shown that the lower transition temperature only is suppressed by rare earth substitution.
Abstract: We report the results of our investigations on the influence of partial substitution of Er and Gd for Dy on the magnetic and magnetoelectric properties of DyFe0.5Cr0.5O3, which is known to be a multiferroic system. Magnetic susceptibility and heat capacity data, apart from confirming the occurrence of magnetic transitions at ~121 and 13 K in DyFe0.5Cr0.5O3, bring out that the lower transition temperature only is suppressed by rare-earth substitution. Multiferroic behavior is found to persist in Dy0.4Ln0.6Fe0.5Cr0.5O3 (Ln = Er and Gd). There is an evidence for magnetoelectric coupling in all these materials with qualitative differences in its behavior as the temperature is changed across these two transitions. Remnant electric polarization is observed for all the compounds. The most notable observation is that electric polarization is seen to get enhanced as a result of rare-earth substitution with respect to that in DyFe0.5Cr0.5O3. Interestingly, a similar trend is seen in the magnetocaloric effect, consistent with the existence of magnetoelectric coupling. The results thus provide evidence for the tuning of magnetoelectric coupling by rare-earth substitution in this family of oxides.

18 citations