Antiferroelectrics and Magnetoresistance in LaSrFeO 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 LaSrFeO 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 Sr ions with 0.5 La ions in the SrFeO 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 LaSrFeO 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 LaSrFeO 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.