The magnetic state of the Co-sublattice in Tb1-xYxCo2

The Tb1-xYxCo2 pseudobinary series has been studied by means of resistivity , magnetic susceptibility and neutron diffraction measurements. According t o the neutron diffraction a long-range magnetic order in this system exists only for x < 0.8. In compounds with the yttrium concentration near x(c) ap proximate to 0.8 a short-range magnetic order and anomalies in the transpor t properties: maximal value of the residual resistivity and large magnetore sistance effect (about - 30%) were observed. We have found that the concent ration dependence of the residual resistivity rho(res) for Tb1-xYxCo2 (as w ell as for other (R1-xYx)Co-2 compounds) correlates with the variation of t he coefficient gamma (linear term of the low-temperature specific heat). In vicinity of x(c) where the Go-magnetic moment is unstable the maximums of rho(res) and gamma can be associated with the large contribution from local ized spin density fluctuations of d-electrons to both electrical resistivit y and specific heat. (C) 1999 Published by Elsevier Science B.V. All rights reserved.