Tuning ferroelectrics to antiferroelectrics in multiferroic LaxSr1−xFe12O19 ceramics

The combination of antiferroelectricity and ferromagnetism in one structure would create new types of multiferroic candidates. Here, we propose a novel type of multiferroic candidate La x Sr 1− x Fe 12 O 19 , whose room temperature state could be tuned from ferroelectrics (FEs) to antiferroelectrics (AFEs) by changing x from 0 to 0.5. The AFE state in La 0.5 Sr 0.5 Fe 12 O 19 remains as a stable phase between − 163 and 233 °C and demonstrates double P – E hysteresis loops which are fully separated by a straight line with zero polarization. La 0.2 Sr 0.7 Fe 12 O 19 , however, exhibits a hybrid FE/AFE state. Both compounds exhibit strong ferrimagnetism. In addition, the La 0.5 Sr 0.5 Fe 12 O 19 ceramic demonstrates strong magnetoelectric coupling and giant magnetoresistance effect. A 1.1 T magnetic field generates electronic polarization of 0.95 μC/cm 2 , reduces the resistance by 117%, enhances dielectric constants by 540% and right shifts the maximum dielectric loss peak by 208 kHz. The combined functional responses provide an opportunity to develop novel multiferroic memories and energy storage devices. Graphical abstract A novel type of multiferroic candidate combines AFE and FM in one single phase of La 0.5 Sr 0.5 Fe 12 O 19 , which also presents strong ME coupling, colossal magnetodielectric (MD) and GMR effects.