Enhanced antiferromagnetic transition and magnetodielectric study in cobalt and holmium co-substituted multiferroic Bi2Fe4O9

摘要: The search for new room temperature magnetoelectric materials future multifunctional device application is the motivation behind preparation of polycrystalline Bi2(1−x)Ho2x Fe4(1−y)Co4y O9 (x = y 0; x 0, 0.02; 0.02, 0 and 0.02) ceramics. Along with substantial variation in antiferromagnetic transition (T N ) substituted samples (BFCO2, BHFO2), co-substituted sample (BHFCO2) shows an enhanced T at i.e. 288 K as compared to parent BFO (250 K). All except BHFO2, depicts a clear irreversibility ZFC-FCW < 360 along opening MH curves, thus indicating onset weak ferromagnetism associated magnetic glassiness studied samples. dielectric measurements reveal unusual oppression/hump around , thereby providing evidence magnetodielectric (MD) coupling, without any possibility magnetoresistance. Moreover, crossover ~ 200 seen BHFO2 BHFCO2 while mechanism explained using mean-field approximation model, validating presence isolated defects due Ho3+. Lastly, all are subjected MD study, where exhibited −0.4% (~7.5 times) MD% effect (~ −0.06%). Confirmation coupling further established from versus plot H later found obey behavior, 'm' value being comparable exponent (1-p) thermoremanent magnetization.