Magnetocapacitance

About: Magnetocapacitance is a research topic. Over the lifetime, 497 publications have been published within this topic receiving 23846 citations.

Room temperature multiferroism in BaCoF4 films prepared by pulsed laser deposition

Abstract: The much lower magnetic ordering temperature of multiferroic fluorides strongly limits their practical applications [J. F. Scott and R. Blinc, J. Phys. 23, 113202 (2011)]. In this paper, (010) oriented BaCoF4 films have been prepared on (0001) Al2O3 substrates by pulsed laser deposition. The clear observation of amplitude and phase hysteresis loops by piezoresponse force microscopy confirms the ferroelectricity at room temperature. In contrast to the antiferromagnetism in bulk BaCoF4 with a much lower Neel temperature of 69.6 K [Eibschutz et al., Phys. Rev. B 6, 2677 (1972)], clear magnetic hysteresis loops are observed in BaCoF4 films, indicating the weak room temperature ferromagnetism. The nearly unchanged saturated ferromagnetic magnetization of about 30 emu/cm3 between 5 K and 300 K suggests that the Curie temperature of BaCoF4 films is much higher than room temperature. Exchange bias is clearly observed, with a blocking temperature of 250 K. Magnetoelectric coupling is demonstrated by the observed magnetocapacitance effect at room temperature.

Magnetic-field-induced polarization and magnetocapacitance in quantum paraelectric EuTiO3

Abstract: EuTiO3 is a quantum paraelectric as well as an antiferromagnet. The most attractive property for EuTiO3 is the magnetoelectric coupling effect. In the present work, we investigate the influence of the external fields on EuTiO3, including the electric field E and magnetic field h. The application of the electric field counteracts the quantum fluctuation and forces the system into an electrically ordered state. The applied magnetic field directly induces the fluctuation of the spin-pair correlation and indirectly influences the dielectric behaviors through the magnetoelectric coupling. In addition, we notice that the contribution of the magnetic field depends closely on the temperature condition and the electric field background. The (p, h, E, T) and (e, h, T) diagrams are presented showing the temperature, magnetic and electric field dependence of the polarization and the dielectric capacitance. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Magnetic-polaron–induced colossal magnetocapacitance in CdCr2S4

Abstract: The origin of colossal magnetoresistance and colossal magnetocapacitance in a CdCr2S4 system was investigated. Thermoelectric-power and electronic spin resonance spectra reveal that the magnetic polaron is responsible for the colossal magnetoresistance in the n-type sample. The existence of magnetic polarons in the paramagnetic insulting matrix forms an intrinsic Maxwell-Wagner system, leading to the appearance of colossal magnetocapacitance. Being consistent with the evolution of magnetic polarons upon cooling, the Maxwell-Wagner system is valid around insulator-metal transition, where the resistance derived from impedance spectroscopy matches perfectly with DC resistance.

Time-Reversal Symmetry Breaking and Consequent Physical Responses Induced by All-In-All-Out Type Magnetic Order on the Pyrochlore Lattice

Abstract: The physical properties of pyrochlore compounds with the all-in-all-out type arrangement of magnetic moments are discussed. The magnetic order can be regarded as a ferroic order of magnetic octupole moments, which does not give rise to macroscopic magnetization but breaks the time-reversal symmetry. As a result of the time-reversal symmetry breaking, the magnetostriction, magnetocapacitance, Voigt magnetooptic effect, and magnetic susceptibility are expected to have a term linear to the external magnetic field. Another striking consequence of the magnetic order is the presence of spontaneous magnetization and scalar spin chirality on the most stable {111} surfaces. This may pave the way for unique surface magnetotransport phenomena.