Field-driven spin reorientation in SmMnO3 polycrystalline powders

Abstract The SmMnO3 perovskite system shows interesting magnetic properties and making them an attractive material for specific technological application. However, these materials on nanosized dimension display properties that can be significantly different from their bulk dimension. In this regard, using the sol-gel method, the successful synthesis of SmMnO3 polycrystalline powders is herein reported. The structure, morphology, vibrational and magnetic properties of the as-produced sample have been investigated. X-ray diffraction pattern shows a single-perovskite SmMnO3 crystalline phase structure, with a crystalline size of ∼70 nm. The room temperature Raman spectrum confirms the formation of the perovskite SmMnO3 crystalline structure observed by XRD. DC magnetic measurements show an antiferromagnetic-like transition at 60 K (TN ≈ 60 K), attributed to the antiferromagnetic ordering of the Mn3+ spins, magnetic measurements also reveal a temperature-induced magnetization reversal phenomenon characterized by the magnetic compensation temperature (Tcomp ≈ 6 K), attributed to antiparallel orientation of weak ferromagnetic Mn3+- and Sm3+-ion magnetic moments induced by Sm3+-Mn3+ exchange interaction. Magnetization loops, recorded from the as-synthesized SmMnO3 sample contain some singularity compared to previous studies of SmMnO3, which are assigned to small particle size and single domain character of the particles, which are characterized by two well-defined anomalies, both connected with the spin inversion phenomena: one at low fields showing increasing and decreasing branches intersecting each other; another at high fields revealing sudden jumps. The study of a Schottky anomaly in the specific heat measurements recorded at low temperatures (below 10 K) under DC magnetic fields (in the range 5–14 T), is consistent with the presence of a field-driven spin reorientation, from antiferromagnetic to a net ferromagnetic order.