Antiferroelectrics and Magnetoresistance in La_0.5Sr_0.5Fe₁₂O₁₉ Multiferroic System

The appearance of antiferroelectrics (AFE) in the ferrimagnetism (FM) system would give birth to a new type of multiferroic candidate, which is significant to the development of novel devices for energy storage. Here we demonstrate the realization of full antiferroelectrics in a magnetic La_0.5Sr_0.5Fe₁₂O₁₉ system (AFE+FM), which also presents a strong magnetodielectric response (MD) and magnetoresistance (MR) effect. The antiferroelectric phase was achieved at room temperature by replacing 0.5 Sr²⁺ ions with 0.5 La²⁺ ions in the SrFe₁₂O₁₉ compound, whose phase transition temperature of ferroelectrics (FE) to antiferroelectrics was brought down from 174 °C to -141 °C, while the temperature of antiferroelectrics converting to paraelectrics (PE) shifts from 490 °C to 234 °C after the substitution. The fully separated double P-E hysteresis loops reveal the antiferroelectrics in La_0.5Sr_0.5Fe₁₂O₁₉ ceramics. The magnitude of exerting magnetic field enables us to control the generation of spin current, which induces MD and MR effects. A 1.1T magnetic field induces a large spin current of 15.6 n A in La_0.5Sr_0.5Fe₁₂O₁₉ ceramics, lifts up dielectric constants by 540%, and lowers the resistance by -89%. The magnetic performance remains as usual. The multiple functions in one single phase allow us to develop novel intelligent devices.