Ferrimagnetism, resistivity, and magnetic exchange interactions in double perovskite La2CrMnO6

Abstract

Although several reports have studied the types of magnetic exchange interactions, the origin of the ferrimagnetism or ferromagnetism, and crystal structure in double perovskite La2CrMnO6, there are still many controversies because of the complexity of structures, valence states and synthesized conditions in this material. To further explore the structure, magnetism, resistivity and exchange interactions, the X-ray diffraction, X-ray photoelectron spectroscopy, AC and DC magnetic measurements, and the resistivity as a function of temperature are performed in this study. The O-type orthorhombic structure (b < c√2 < a) is confirmed and this structure can effectively remove the effects of Jahn-Teller distortions. The ferrimagnetic transition and the charge localization feature are confirmed by the magnetic and electric measurements, and the ferrimagnetic transition is mainly due to the Cr3+–O2−–Mn3+ double-exchange interactions. The Arrhenius law is used to confirm a thermally activated mechanism just below the ferrimagnetic transition temperature, which has a strong correlation with the charge localization behavior.