Single Crystal Growth and Fermi Surface Properties of an Antiferromagnet UPdGa₅

Abstract

We have succeeded in growing a high-quality single crystal of an antiferromagnet UPdGa 5 by the Ga-flux method with the off-stoichiometric composition of U : Pd : Ga = 1 : 2 : 7.3. The Néel temperature T N = 30.5 K is found to increase with increasing the residual resistivity ratio (RRR) and becomes constant for a high-quality single crystal sample whose RRR is larger than 50. The electronic state has been investigated by the de Haas–van Alphen experiment, indicating the similar cylindrical Fermi surfaces as in an antiferromagnet UPtGa 5 . We have also studied the pressure effect by measuring the electrical resistivity. The Néel temperature decreases with increasing pressure and becomes zero at 3.1 GPa. The antiferromagnetic state is changed into the paramagnetic state above 3.1 GPa.