Giant electric field–controlled magnetism in Bi0.86Sm0.14FeO3 multiferroic ceramics with Pna21 symmetry

Abstract

AbstractIn the present work, Bi0.86Sm0.14FeO3 ceramics with near Pna21 single‐phase structure were obtained by a repeated longtime sintering process, and the dielectric, ferroelectric, and magnetic characteristics were determined together with the magnetoelectric coupling coefficient. The evolution of Pna21 symmetry was revealed by transmission electron microscope analysis, and the ferroelectric transition from Pbnm to Pna21 was determined by differential scanning calorimetry analysis together with the dielectric characterization, and the Curie temperature was determined as 195°C. The saturated polarization–electric field (P–E) hysteresis loop was obtained with Pr = 12.2 μC cm−2, and the unlocking of ferromagnetism was confirmed by the apparent magnetization–magnetic field (M–H) hysteresis loop with Mr = 77.4 emu mol−1. The giant electric field–controlled magnetism was due to the Pna21/R3c field–induced transition, which was confirmed by both structure analysis and theoretical calculation, and the change of remanent magnetization under an electric field was achieved up to 44.8 emu mol−1 (57.9%), which was much bigger than that of rare‐earth (RE)‐substituted BiFeO3 ceramics without optimizing Pna21 phase fraction. The present results might significantly deepen the physical understanding of Pna21 phase and subsequently provide new hints on further enhancing electric field–controlled magnetism in RE‐substituted BiFeO3 multiferroic ceramics.