The Structure and Weak Ferromagnetism of the Double Layered Cuprocobaltate: Y2SrCu0.6Co1.4O6.5

ietveld refinement of the X-ray powder diffraction (XRPD) pattern confirms that Y2SrCu0.6Co1.4O6.5 is isostructural to 2SrCuFeO6.5. Unlike its Fe-analog which is antiferromagnetic, Y2SrCu0.6Co1.4O6.5 behaves as a three-dimensional (3D) erromagnet below TC=385 K with a spontaneous magnetic moment per formula unit of only mus=0.07 muB extrapolated to =0 K. We concluded that this weak ferromagnetism (WFM) originates from Dzyaloshinsky–Moriya (D–M) spin canting echanism based on the observation of T2 dependence of the low-temperature magnetization. The electrical resistance of intered samples shows an exponential dependence on temperature exp(T0/T)alpha with alpha=1/2 in the 185–570 K emperature range, which indicates the conduction mechanism is within variable range hopping (VRH) regime with long-range oulomb interaction between the carriers. Y2SrCu0.6Co1.4O6.5 does not show any significant magneto-resistance effect in the 00–400 K temperature range.