NewferromagneticLa3Co2TaO9 doubleperovskite:Structuraland magneticproperties

V.C. FUERTES; M.C.BLANCO; D.G.FRANCO; J.M.DEPAOLI; E.V.PANNUNZIOMINER; R.D.SANCHEZ; M.T.FERNANDEZ-DıAZ; R.E.CARBONIO

PHYSICA B - CONDENSED MATTER

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2009 vol. 404 p. 2717 - 2719

0921-4526

The new double perovskite La3Co2TaO9 has been prepared by a solid state procedure.The crystal and magnetic structures have been studied from X-ray powder diffraction (XRPD) and neutron powder diffraction (NPD) data. Rietveld refinements were performed in the monoclinic space group P21/n. The structure consists of an ordered array of alternating B0O6 and B00O6 octahedra sharing corners, tilted along the three pseudocubic axes according to the Glazer notation abc+. Rietveld refinements show thatat RT the cell parameters are a =5.6005(7)A˚ , b= 5.6931(7)A˚ , c=7.9429(9)A˚ and b =89.9539(7)1, and the refined crystallographic formula of this ??doubleperovskite??can be written as La2(Co)2d(Co1/3Ta2/3)2cO6. Magnetization measurements and low-temperature NPD data show that the perovskite is a ferromagnet with TC=72K. At high T it follows the Curie?Weiss law with an effective magnetic moment of 3.82mB per Co ion which is very close to spin only Co2+ (HS).