Full Antiferroelectric Performance and GMR Effect in Multiferroic La0.75Ba0.25Fe12O19 Ceramic

The potential application of multiferroic materials in new electronic devices attracts more and more attention from people either in an academic field or industry. This paper reports that M-type lanthanum-doped barium ferrite (La0.75Ba0.25Fe12O19) demonstrates full antiferroelectric (AFE) and excellent magnetoelectric coupling effects at room temperature, while its AFE phase displays a zero macroscopic net polarization. The dramatic change in the dielectric constant near the Curie temperature far below room temperature represents the transition from ferroelectrics (FE) to antiferroelectrics. The fully separated double electric polarization hysteresis (P-E) loops confirmed its AFE performance. Its E-F and E-A are located at 1100 kV/cm and 850 kV/cm, respectively. The large M-H loop showed a strong magnetic property simultaneously. The UV-Vis-NIR optical spectrum revealed that La0.75Ba0.25Fe12O19 is also a semiconductor, whose direct bandgap energy (E-g) was determined to be 1.753 eV. Meanwhile, La0.75Ba0.25Fe12O19 showed strong ME coupling and a GMR effect. A 1.1 T magnetic field reduced its resistance by 110% at 30 kHz. The multiple functions combined in one phase would create new options for high energy storage capacitors, microactuators, pyroelectric safety sensors, cooling devices, and pulsed power generators and so on, as well as great opportunities for generating new electronic devices with active magnetoelectric coupling effects.