Cryogenic temperature relaxor-like dielectric responses and magnetodielectric coupling in Aurivillius Bi_5Ti_3FeO_(15) multiferroic thin films

摘要

Dielectric responses and magnetodielectric (MD) behavior of Aurivillius Bi_5Ti_3FeO_(15) multiferroics were systemically studied at cryogenic temperatures. Dielectric anomaly at ～145K was found by the temperature dependent dielectric spectroscopy, and relaxor-like relaxation dynamics was further confirmed unambiguously. Besides the two abnormal MD transitions at about 98 K and 220 K, remarkable MD couplings were observed near relaxation peak over the whole frequency range of 10~2-10~6 Hz. Finally, the possible mechanisms Of the relaxation and MD properties were discussed in association with the occurrence of local Fe-O nano-clusters because of the antisite disorder defects in Aurivillius multiferroic phases.