Neutron diffraction and magnetization study of La0.7Ca0.3FeO3

Abstract

A neutron diffraction (ND) study at room temperature was carried out on La0.7Ca0.3FeO3 (LCFO). Magnetization studies have described LCFO as a canted-antiferromagnet, with ordering temperature above 400 K. The canting of spins was evident from the field cooled magnetization increasing (FM-like) and, on the other hand, the zero field cooled magnetization decreasing (AFM-like) with decreasing temperature. From the isothermal magnetization, M(H) loop taken at 300 K in applied fields up to 40 kOe, the coercive field (Hc) is around 3 kOe and the remanent moment (Mr) is 0.01 μB. Rietveld refinement of the ND pattern for the crystalline and magnetic structures shows that LCFO crystallizes in an orthorhombic unit cell with space group Pnma, and the magnetic moment observed at room temperature is 2.23 μB/Fe ion. Fe is seemingly between Fe3+(67%) and Fe4+(33%) states with an average valence of 3.3. The Rietveld analysis also shows that the moments are slightly canted in the ab plane in conformity with the magnetization data.