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Polar magnets are a family of promising candidates for future magnetoelectric (ME) applications. In particular, the ME effect is recognized for its potential use in low-power electronic devices. However, searching for materials with a sufficiently strong ME effect remains the core issue. In this work, we present a systematic investigation on oxide compound Sm2BaCuO5, including the characterization on structural, magnetic, specific heat, dielectric, and pyroelectric behaviors. The intrinsic linear ME effect is revealed, and two successive antiferromagnetic phase transitions occurring at temperatures of TN1 ∼ 5 K and TN2 ∼ 23 K are found, respectively. While a magnetic field induced electric polarization emerges below TN2 and this polarization increases with the magnetic field in an almost linear manner, another weak pyroelectric current peak is detected around TN1. Furthermore, remarkable responses of both electric polarization to the magnetic field and magnetization to the electric field are demonstrated. It is suggested that the intriguing magnetic interactions play the core roles in generating the ferroelectricity and ME effect in this Sm2BaCuO5 compound. [ABSTRACT FROM AUTHOR]

Layered perovskites A3M2O7 are known to exhibit the so-called hybrid improper ferroelectricity. Despite experimentally confirmed cases (e.g., nonmagnetic M = Ti and Sn), the ferroelectricity in magnetic Ca3Mn2O7 remains a puzzle. Here, the structural, ferroelectric, magnetoelectric, and optical properties of Ca3Mn2O7 are systematically investigated. Switchable polarization is directly measured, demonstrating its ferroelectricity. In addition, magnetoelectric response is also evidenced, implying the coupling between magnetism and ferroelectricity. Furthermore, strong visible light absorption is observed, which can be understood from its electronic structure. Its direct and appropriate bandgap, as well as wide conducting bands, makes Ca3Mn2O7 a potential candidate for ferroelectric photoelectric applications. [ABSTRACT FROM AUTHOR]

Sol-gel process was adopted to prepare BiFeO3 films. BiFeO3 films were deposited on LaNiO3 coated Si(100) substrates annealed at 500 and 550 °C, respectively. The X-ray diffraction results reveal that BiFeO3 film has a rhombohedrally distorted perovskite structure with space group R3 c. The film annealed at 500 °C has larger remnant polarization ( Pr) of 35.3 µC/cm2. For the film annealed at 550 °C, smaller remnant polarization of Pr=4.8 µC/cm2 is observed for its low breakdown electric field. Lower leakage conduction is observed in the film annealed at 500 °C at low applied field. [ABSTRACT FROM AUTHOR]