Coupling between the magnetism and dielectric properties inEu1−xBax

Abstract

The dielectric constant of the quantum paraelectric EuTiO 3 exhibits a sharp decrease at about 5.5 K, at which temperature antiferromagnetic ordering of the Eu spins simultaneously appears, indicating coupling between the magnetism and dielectric properties. A similar feature has also been detected in Eu 1Ϫx Ba x TiO 3 (0Ͻxр0.2). The random-bond model within the framework of the transverse-field Ising model and the site dilution model based on the Heisenberg model are successfully applied to the Eu 1Ϫx Ba x TiO 3 electrical and magnetic subsystems, respectively. By adding an appropriate coupling term between the magnetic and electrical subsystems, which is related to the interaction of the Heisenberg spin and pseudospin, we investigate intrinsic coupling between the magnetic and electrical subsystems and successfully obtain its special dielectric constant, which is in good agreement with the experimental data.

First-principles prediction of oxygen octahedral rotations in perovskite-structure EuTiO3

“…16,17 Likewise "chemical strain," i.e., doping at the A site with larger divalent ions, has been shown to induce ferroelectricity, e.g., in alloys with BaTiO 3 . 18 The latter is particularly intriguing, as multiferroic (Eu,Ba)TiO 3 ceramics fulfill the requirements for a solid state search for the electric dipole moment of electron. 19 In this work, we revisit bulk EuTiO 3 , with a particular focus on the possibility that the ground state is not, in fact, the high-symmetry P m3m perovskite prototype, but a lower symmetry structure possessing rotations or tilts of the oxygen octahedra.…”

Giant magnetocaloric effect in magnetoelectric Eu1-xBaxTiO3

“…In recent experiments, K. Z. Rushchanskii et al 15 found ferroelectric hysteresis loop around 130 K and antiferromagnetism below T N = 1.9 K in the same composition. While H. Wu et al 16 investigated theortically the intrinsic coupling between magnetism and dielectric properties in Eu 1-x Ba x TiO 3 (0 ≤ x ≤ 0.2), T. Wei et al 17 reported dielectric constant and electrical polarization in polycrystalline samples (0 ≤ x ≤ 1). It was found that while x ≤ 0.15 is paraelectric, ferroelectricity develops in x > 0.2 as evidenced by ferroelectric hysteresis loop.…”

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

“…The magnetoelectric interaction is described by Eq. (4), which has been first established to investigate the impurity effect [4]. As has been pointed out in the previous section, two kinds of coupling form have been proposed: one is based on the soft-mode theory [12] and the other is based on TIM [4].…”

“…Here, the external fields include the electric field E and the magnetic field h, and the dielectric properties include the polarization p and the dielectric capacitance ε . We think our work provides a thorough research into the magnetodielectric properties of EuTiO 3 , and it also helps us to better understand the doped system [4].…”

“…According to the soft-mode theory, it's the fluctuation of the spin-pair correlation that affects the behavior of the soft-mode and brings about the dielectric anomaly. Thereafter, in order to investigate the influence of the impurities on EuTiO 3 , the coupling form has been rewritten within the Transverse Ising model (TIM) [4]. Investigation on Eu 1-x Ba x TiO 3 has shown that perturbation from the doped Ba ions indeed destroys the paraelectric phase and forces the ferroelectric phase.…”