Temperature dependent neutron powder diffraction study of the Laves phase compound TbCo2

The structure, magnetization and magnetostriction of Laves phase compound TbCo2 are investigated by temperature dependent high resolution neutron powder diffraction. The compound crystallizes in the cubic Laves phase C15 structure above its Curie temperature T-c and exhibits a rhombohedral distortion (space group R (3) over barm) below T-c. By an appropriate extrapolation of the temperature factor of Co atom above Tc, the Rietveld refinement of the neutron powder diffraction data of the rhombohedral structure converges satisfactorily and reveals that the moments of Co1(3b) and Co2(9e) are almost equal. Tb moment follows well the Brillouin function. The total magnetic moment of TbCo2 is about 5-8mu(B)/f.u., the anisotropic magnetostriction constant lambda(111) is about 4.6 x 10(-3) and the volume magnetostriction omega(s) is about 8.7 x 10(-3) at 14 K. (C) 2004 Elsevier B.V. All rights reserved.