Magnetic influence on the frequency of the soft-phonon mode in the incipient ferroelectric EuTiO3

Abstract

The dielectric constant of the incipient ferroelectric EuTiO${}_3$ exhibits a sharp decrease at about 5.5K, at which temperature antiferromagnetic ordering of the Eu spins simultaneously appears, indicating coupling between the magnetism and dielectric properties. This may be attributed to the modification of the soft-phonon mode, $T_{1\mu }$, which is the main contribution to the large dielectric constant, by the Eu spins(7${\mu }_B$ per Eu). By adding the coupling term between the magnetic and electrical subsystems as $-g\sum _l\sum _{<i,j}{q}_l^2\overrightarrow{S_i}\cdot \overrightarrow{S_j}$ we show that the variation of the frequency of soft-phonon mode depends on the spin correlation between the nearest neighbors Eu spins and is substantially changed under a magnetic field.

arXiv comment13 pages, 4 figures

References in corpus (1)

• Effect of quantum fluctuations on structural phase transitions in SrTiO_3 and BaTiO_3

Cited by in corpus (5)

• Analogies of structural instabilities in EuTiO3 and SrTiO3
• Magnetodielectric effect and optic soft mode behaviour in quantum paraelectric EuTiO3 ceramics
• First-principles prediction of oxygen octahedral rotations in perovskite-structure EuTiO3
• Phonon Softening and Dispersion in EuTiO3
• Magnetoelastic relaxations in EuTiO3