Nuclear structure and magnetic properties of perovskite compounds La1−xNdxFe0.5Cr0.5O3 (x = 0.1, 0.15 and 0.2)

Perovskite oxides with the composition La1−xNdxFe0.5Cr0.5O3 (x = 0.10, 0.15 and 0.20) have been studied. The samples have been prepared using the standard solid-state reaction method in air. The X-ray and neutron diffractograms indicates that the samples crystallize in the orthorhombic perovskite structure with space group Pnma (No. 62). The Nd-substitution causes minor changes in the cell parameters and bond lengths but the nuclear structure remains orthorhombic in the whole range of substitutions and in the temperature range of 10-700 K. The magnetic structure of the samples at room temperature and below is G-type antiferromagnetic with an average magnetic moment of the Fe/Cr ions of 3.29(3) μB/atom at 10 K independent of the Nd content. At room temperature the average magnetic moment of the Fe/Cr ions reduces to 1.23 μB/atom. At temperatures below 250 K a weak but increasing uncompensated spontaneous magnetic moment develops that reaches a magnitude of about 0.5 emu/g (or 0.02 μB per Fe/Cr site) at 10 K. This moment saturates rather rapidly in the magnetization versus magnetic field curve and is at higher field superposed on the response of the antiferromagnetic spin system.