Study on antiferromagnetism of U(Pt1-xPdx)(3) by heat capacity measurement

We report the magnetic phase diagram versus external magnetic held for U(Pt 1-xPdx)(3). The decrease of T-N by an external field is largely anisotropic with respect to the field direction. The large values of C/T at low T are attributed to the heavy fermion state in the AF ordered state. We have anal yzed log T-dependences of the heat capacity below T-N where effects of the antiferromagnetic spin fluctuations are dominant. We also observed an activ ation type T-dependent heat capacity associated with magnetic transition, i ndicating that the magnetic ordering is like an SDW transition with opening of a gap over some part of the Fermi surface. (C) 1999 Elsevier Science B. V. All rights reserved.