Abnormal magnetic ordering and ferromagnetism in perovskite ScMnO3 film

Abstract

Bulk multiferroic ScMnO3 is the stable hexagonal phase, and it is very difficult to prepare its perovskite orthorhombic phase even under high pressure. We fabricated the orthorhombic ScMnO3 thin film by pulsed laser deposition through suitable substrate LaAlO3 and found that nano-scale twin-like domains are naturally formed in the thin film. Magnetic properties of the orthorhombic ScMnO3 thin films show that, besides normal antiferromagnetic ordering at 47 K, an anomalous magnetic transition occurs at 27 K for 60 nm film and at 36 K for 150 nm film only along the c-axis, which is absent in the ab-plane. Moreover, the second magnetic transition for both films is suppressed when the applied field increases from 1 kOe to 10 kOe. In addition, the ferromagnetism shows up in both films at 10 K, and saturation magnetization increases dramatically in 60 nm film compared with 150 nm film. We propose that the second magnetic transition might be more of lattice strain effect and also related to magnetism-induced ferroelectric polarization in orthorhombic RMnO3 thin films and low-temperature ferromagnetic properties in our films originate from the nano-scale twin-like domain structure.