LOW-TEMPERATURE MAGNETIC-PROPERTIES OF HIGH-TC GDXY1-X-BA-CU OXIDE

Low-temperature magnetic susceptibilities of high Tc compound of GdxY1-xBa-Cu oxide have been studied down to 0.3 K and at the magnetic fields up to 8 T. For the case of x=1.00, the Neel temperature of antiferromagnetic ordering is about 2.3 K. The decrease of the Neel temperature is almost proportional to that of the Gd concentration. However, in the case of x=0.60, the Neel temperature becomes lower and deviates from the linear dependence in the high Gd concentrations. While the linear dependence of the Neel temperature can be expected from a decrease of the dipole-dipole interaction between Gd ions, above drastic decrease of the Neel temperature can not be explained by such a simple magnetic interaction.