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The hexagonal rare earth ferrites h -RFeO 3 (R = rare earth element) have been recognized as promising candidates for a room-temperature multiferroic system, and the primary issue for these materials is how to get a stable hexagonal structure since the centrosymmetric orthorhombic structure is generally stable for most RFeO 3 at room-temperature, while the hexagonal phase is only stable under some strict conditions. In the present work, h -Lu 1- x In x FeO 3 ( x = 0-1) thin films were prepared on a Nb-SrTiO 3 (111) single-crystal substrate by a pulsed laser deposition (PLD) process, and the multiferroic characterization was performed at room temperature. With the combined effects of chemical pressure and epitaxial strain, the stable hexagonal structure was achieved in a wide composition range ( x = 0.5-0.7), and the results of XRD (X-ray diffraction) and SAED (selected area electron diffraction) indicate the super-cell match relations between the h -Lu 0.3 In 0.7 FeO 3 thin film and substrate. The saturated P - E hysteresis loop was obtained at room temperature with a remanent polarization of about 4.3 μC/cm 2 , and polarization switching was also confirmed by PFM measurement. Furthermore, a strong magnetoelectric coupling with a linear magnetoelectric coefficient of 1.9 V/cm Oe was determined, which was about three orders of magnitude larger than that of h -RFeO 3 ceramics. The present results indicate that the h -Lu 1- x In x FeO 3 thin films are expected to have great application potential for magnetoelectric memory and detection devices.

Single-phase materials that combine electric polarization and magnetization are promising for applications in multifunctional sensors, information storage, spintronic devices, etc. Following the idea of a percolating network of magnetic ions (e.g., Fe) with strong superexchange interactions within a structural scaffold with a polar lattice, a solid solution thin film with perovskite structure at a morphotropic phase boundary with a high level of Fe atoms on the B site of perovskite structure is deposited to combine both ferroelectric and ferromagnetic ordering at room temperature with magnetoelectric coupling. In this work, a 0.85BiTi 0.1 Fe 0.8 Mg 0.1 O 3 -0.15CaTiO 3 thin film has been deposited by pulsed laser deposition (PLD). Both the ferroelectricity and the magnetism were characterized at room temperature. Large polarization and a large piezoelectric effective coefficient d 33 were obtained. Multifield coupling of the thin film has been characterized by scanning force microscopy. Ferroelectric domains and magnetic domains could be switched by magnetic field ( H), electric field ( E), mechanical force ( F), and, indicating that complex cross-coupling exists among the electric polarization, magnetic ordering and elastic deformation in 0.85BiTi 0.1 F e0.8 Mg 0.1 O 3 -0.15CaTiO 3 thin film at room temperature. This work also shows the possibility of writing information with electric field, magnetic field, and mechanical force and then reading data by magnetic field. We expect that this work will benefit information applications.