Hydrothermal synthesis, morphology, structure, and magnetic properties of perovskite structure LaCr1−xMnxO3 (x = 0.1, 0.2, and 0.3)

Abstract

We report the synthesis of LaCr_1−xMn_xO₃ (x = 0.1, 0.2, and 0.3) single crystal microcubes via a mild hydrothermal method. The as-synthesized LaCr_1−xMn_xO₃ samples were crystallized into the Pnma space group with uniform particle size and cubic morphology. The lattice parameters increased as the doping level of Mn increased from x = 0.1 to 0.3. XPS characterization of the samples showed that the valence states of Cr and Mn are both +3. A temperature-dependent magnetization study indicated a clear transition point of canted-antiferromagnetic to paramagnetic behaviour from 3–380 K, with their Neel transition points located between 246–265 K. The isothermal magnetic hysteresis of the LaCr_1−xMn_xO₃ samples show that they possess the same coercive field strength but a linear increment of remnant magnetization with increasing Mn doping level. A temperature-dependent magnetic entropy change study indicated that the samples show a maximum ΔS of 0.4247 J kg⁻¹ K⁻¹ for LaCr_0.7Mn_0.3O₃ at 40 K for ΔH = 6 T. Arrott plots of M²versus H/M indicate a second-order magnetic phase transition for all of the as-synthesized LaCr_1−xMn_xO₃ samples. All these results suggest that the promotion of magnetization was successfully performed by hydrothermally doping Mn in a LaCrO₃ lattice. This study provides a design and synthesis strategy to increase the ferromagnetic exchange in weak magnetization materials.