Seemingly anisotropic magnetodielectric effect in isotropic EuTiO3 ceramics


Anisotropic magnetodielectric effect was observed at 0.3 K in the low-frequency dielectric spectra of antiferromagnetic EuTiO3 ceramics. The effect was theoretically explained by a demagnetizing field and confirmed by magnetization measurements. THz refractive index revealed also a large anisotropy in external magnetic field. This anisotropy is due to activation of the ferromagnetic resonance only if the magnetic field is applied perpendicularly to the magnetic component of the THz radiation.

Magnetic field dependence of EuTiO3 permittivity
Left: Magnetic field dependence of EuTiO3 permittivity measured for electric field applied perpendicularly to the sample plane, and with the static external magnetic field B in either of two orientations marked in the figure. Inset: Dependence of the permittivity ratio for two orientations of the magnetic field. 
Rigth: THz refractive index measured at three magnetic fields applied perpendicularly to the electric vector of THz radiation. Inset: Magnetic field dependence of the magnon frequency measured at 2 and 15 K.

Contact person: Stanislav Kamba