Magnetic interactions in HoCr1-xFexO3 (x = 0, 0.2) investigated by neutron powder diffraction

•The temperature dependent magnetism of HoCr1-xFexO3 (x = 0, 0.2) were investigated by neutron diffraction.•Cr3+ moment follows a mean field theory while Ho3+ follows a spin 1/2 model.•An magneto-elastic strain was observed accompanying with the ordering of Cr3+.

The temperature dependent magnetism of Fe-doped rare earth orthochromite HoCr1-xFexO3(x = 0, 0.2) was investigated by neutron powder diffraction. It is found that the magnetism of Cr(Fe)3+ can be well understood within mean field theory, while the ordering of Ho3+ was induced by the Cr(Fe)3+ sublattice and can be satisfyingly described by an effective S = 1/2 model. The absences of both the most common GxFz configuration of Cr3+ and the ordering of Ho3+ caused by Ho-Ho interaction evidence a strong Ho3+-Cr3+ interaction which dominates this system. On the other hand, a remarkable magnetoelastic strain was observed accompanying the Cr(Fe)3+ ordering. An analysis based on the equation of state with a Grüneisen approximation was performed and revealed magnetic origin of this strain.