Spin reorientation inNdFe0.5Mn0.5O3: Neutron scattering andab initiostudy

The structural, magnetic, and electronic properties of ${\mathrm{NdFe}}_0.5{\mathrm{Mn}}_0.5{\mathrm{O}}₃$ have been studied in a comprehensive manner using various experimental and theoretical methods. Mn/Fe sublattice of the compound orders into a G-type antiferromagnetic phase close to 250 K where the magnetic structure belongs to ${\mathrm{\ensuremath{\Gamma}}}₁$ irreducible representation (${G}_y$) unlike ${\mathrm{\ensuremath{\Gamma}}}₄$ (${G}_x$) representation observed in most of the orthoferrites and orthochromites. The magnetic structure undergoes a complete spin reorientation transition with temperature between 75 and 25 K where the magnetic structure exists as a sum of two irreducible representations (${\mathrm{\ensuremath{\Gamma}}}₁+{\mathrm{\ensuremath{\Gamma}}}₂$). At 1.5 K, the antiferromagnetic structure belongs entirely to ${\mathrm{\ensuremath{\Gamma}}}₂$ representation (${G}_z$) with a small ferromagnetic component (${F}_x$) due to Nd. The unusual spin reorientation and correlation between magnetic ground state and electronic structure have been investigated using phenomenological theory and first-principles calculations within GGA+$U$ and GGA+$U$+SO formalisms.