Disorder-driven spin-reorientation in multiferroic h-YMn1−xFexO3

Abstract

Magnetic structure evolution of multiferroic hexagonal YMn1−xFexO3 (x = 0, 0.05, and 0.1) has been studied by carrying out detailed temperature-dependent neutron diffraction at zero and 5 T fields. Thermodynamic data confirm antiferromagnetic ordering at TN in all the compositions. Our sub-TN neutron diffraction results assign the magnetic structure of pure YMnO3 to Γ1 irreducible representation. Over the perturbative-doping range, magnetic structure changes via Γ1 + Γ2 for YMn0.95Fe0.05O3 on to Γ2 for YMn0.9Fe0.1O3, as the maiden compositional analogue of spin-reorientation; its occurrence in temperature-domain already reported for several manganites. Moreover, while the large thermal isostructural changes observed above TN are subdued in the ordered state, small alterations by the applied 5 T-field are relatively uniform across, confirming strong magneto-elastic nature of the system. Decrease of the ordered magnetic moment (μord) and planar magnetic frustration noted with Fe-doping is enhanced by the applied field, apparently through canting.