Determination of the magnetic structures in orthoferrite CeFeO3 by neutron powder diffraction: first order spin reorientation and appearance of an ordered Ce-moment

Abstract

High resolution and high intensity neutron powder diffraction are used to determine the temperature dependence of the crystallographic and magnetic structure of the orthoferrite CeFeO3. The high temperature G x -type magnetic coupling of the Fe-sublattice described by the Γ4 (G x A y F z ) irreducible representation changes at the spin reorientation temperature T SR = 228 K to a G y -type coupling of Γ1 (A x G y C z ). The spin reorientation is of first order and sees a hysteresis of about 2.5 K at T SR. Below 35 K faint magnetic peaks reflecting C z type magnetic coupling appear and are argued to be related to the Ce-sublattice. Magnetic moments at 2 K amount to μ Fe = 4.15 μ B and μ Ce = 0.11 μ B. CeFeO3 is only the second RFeO3 compound after DyFeO3 showing this ground state magnetic structure of the Fe-sublattice. The orthorhombic structure Pbnm is kept over the whole temperature range.