Phase behavior and some properties of LaMn1−xRhxO3 solid solution

Structure and magnetic and electrical properties of the polycrystalline compounds LaMn_1−xRh_xO₃ (0 < x ≤ 1) have been investigated. The samples were characterized by X-ray diffraction and Rietveld refinement which confirmed the space group Pnma (No. 62) for all compositions at room temperature. A transformation from O′- to O-type orthorhombic structure is seen near x = 0.6 tending to make the phase unstable. The electrical conductivity measurement shows semiconducting property above room temperature with a rather low activation energy for Mn-rich compositions. Compounds in the region 0.1 ≤ x ≤ 0.9 show ferromagnetic property but the substitution of Rh³⁺ ion for Mn³⁺ ion suppresses the ferromagnetism that results in reducing the Curie temperature, T_C.