MAGNETIC AND ELECTRICAL-PROPERTIES OF GDCU2

We measured the electrical resistivity, specific heat and de Haas-van Alphen (dHvA) oscillation of an antiferromagnetic compound GdCu2. The magnetic entropy, which was obtained from the specific heat, reaches R ln8 above 47 K, which is close to the Neel temperature of 40 K. The dH vA branches both in the antiferromagnetic state and the field-induced ferromagnetic state are highly different from those of a non-magnetic reference compound YCu2 or PrCu2. The Fermi surface in GdCu2 is most l ikely altered by the magnetic state.