Magnetic and dielectric properties of multiferroic Eu0.5Ba0.25Sr0.25TiO3 ceramics

TL;DR

This study explores the dielectric and magnetic properties of Eu0.5Ba0.25Sr0.25TiO3 ceramics, revealing ferroelectric and antiferromagnetic phases, and suggests potential for electron electric dipole moment measurements.

Contribution

It provides new insights into the multiferroic behavior of Eu0.5Ba0.25Sr0.25TiO3, including phase transition mechanisms and structural details, with implications for quantum measurements.

Findings

Ferroelectric transition near 130 K with soft mode behavior.

Antiferromagnetic order below 1.8 K.

Lower coercive field compared to Eu0.5Ba0.5TiO3.

Abstract

Dielectric and magnetic properties of Eu0.5Ba0.25Sr0.25TiO3 are investigated between 10 K and 300 K in the frequency range from 10 Hz to 100 THz. A peak in permittivity revealed near 130 K and observed ferroelectric hysteresis loops prove the ferroelectric order below thistemperature. The peak in permittivity is given mainly by softening of the lowest frequency polar phonon (soft mode revealed in THz and IR spectra) that demonstrates displacive character of the phase transition. Room-temperature X-ray diffraction analysis reveals cubic structure, but the IR reflectivity spectra give evidence of a lower crystal structure, presumably tetragonal I4/mcm with tilted oxygen octahedra as it has been observed in EuTiO3. The magnetic measurements show that the antiferromagnetic order occurs below 1.8 K. Eu0.5Ba0.25Sr0.25TiO3 has three times lower coercive field than Eu0.5Ba0.5TiO3, therefore we propose this system for measurements of electric dipole moment of electron.