Role of dipole relaxation in measuring electric polarization in type‐II multiferroics

Abstract

Dedicated to Prof. Antonie Maignan on his 60 th birthday.Type-II multiferroics typically have significantly lower polarization values compared to type-I multiferroics. As a result, pyrocurrent measurements are often employed to estimate their electric polarization. However, when the magnitude of the pyrocurrent is overshadowed by faster dipole relaxation and thermally stimulated free charge carriers, the method becomes inadequate. Here, we demonstrate the effectiveness of the DC bias current technique in overcoming the limitation of pyro-electric current measurement using two examples. Our findings reveal that the DC bias current signal is more sensitive than pyroelectric current measurements and can be used to characterize a type-II multiferroic material, quantitatively and qualitatively, with small polarization. Additionally, we discuss the role of dipole relaxation rate in measuring electric polarization and explain it in terms of dipolar interaction and thermal energy.