Dr. Seungwoo Song with Prof. Hyun Myung Jang and colleagues Pohang University of Science and Technology (POSTECH) have clarified why the measured remanent polarization of orthorhombic GaFeO3 (o-GFO), a prominent ferrite owing to its piezoelectricity and ferrimagnetism, is about 50 times smaller than its predicted value. Their research was published in NPG Asia Materials.
Multiferroics are rare materials that simultaneously show ferroelectricity and ferromagnetism, making them potentially useful for sensors and electrically controllable magnetic memories. By growing thin films of the multiferroic material orthorhombic GaFeO3 on cubic and hexagonal substrates, Prof. Jang and Dr. Song have observed ferroelectric polarization switching that has an extraordinarily high coercive field at room temperature. Numerical calculations revealed that this switching has a remarkably high activation energy.
This finding both explains the unusually high coercive field and clarifies the puzzling discrepancy between observed values for the remanent polarization of orthorhombic GaFeO3 and those calculated in previous studies.
The research was supported by the BK21 PLUS program and the National Research Foundation of Korea.