Abstract:
Using neutron diffraction, x-ray diffraction, magnetization measurement and magnetic x-ray scattering on an oxygen-deficient double perovskite YBaCuFeO5 (YBCFO), we report a detailed study of its magnetic phase transition. From magnetization measurement and neutron diffraction, YBCFO shows commensurate-incommensurate magnetic phase transition at TN~ 175 K. The incommensurate phase was confirmed to be a spiral spin ordering with a propagation wavevector along the c-axis, and the magnetic moments lie on the ab-plane. This spiral spin structure was further determined to consist of two components of Cu2+ and Fe3+ using magnetic x-ray scattering, i.e., forming a double-helical spin ordering.