title: Fresh look at the mystery of magnetization reversal in YVO3.
abstract: Phase transitions and detailed magnetic properties of polycrystalline AP-YVO3.00(1) (prepared at ambient pressure by a conventional solid-state method) and polycrystalline HP-YVO3.04(1) and HP-YVO3.05(1) (AP-YVO3 treated at 6 GPa and 1600 K during 130 and 15 min, respectively) were investigated. The three samples showed a remarkable exchange bias (EB) effect. HP-YVO3.04 and HP-YVO3.05 had similar chemical composition, crystallographic parameters, and particle size, but their magnetic properties were qualitatively different. EB was negative at all temperatures in AP-YVO3 and HP-YVO3.05, resulting in the absence of magnetization reversal (MR). Positive EB was observed in HP-YVO3.04 between T(N2) = 71 K and T* = 88 K resulting in MR or negative magnetization between those temperatures. It was demonstrated that polycrystalline HP-YVO3.04 behaved similar to single crystals of YVO(3+δ). By the careful control of the trapped magnetic field, measurement conditions were found under which no MR occurred in HP-YVO3.04 at moderate magnetic fields, indicating that MR is not an intrinsic property of YVO(3+δ). A drastic effect of trapped magnetic fields on MR and memory effects were observed. The importance of an "insignificant" anomaly at T(FM) = 140 K for MR was suggested. We also suggested that "positive exchange bias", "defects", "interfaces", and "pinning" should be keywords for understanding YVO3 and probably other perovskite materials with the MR effect.
authors.affiliation: National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. alexei.belik@nims.go.jp
authors.forename: Alexei A
authors.initials: AA
authors.lastname: Belik