Magnetostriction of REBa2Cu3O7−δ

The magnetostriction (MS) of REBa2Cu3O7−δ (RE=Y, Nd, Eu, Gd, Ho, Er, Yb) is reported as a function of magnetic field and temperature forH 1 T. The MS is much larger when the rare earth carries a magnetic moment, as usual, but the volume MS observed with moment carrying REBa2Cu3O7−δ is larger than that of nonsuperconducting intermetalics. This effect is explained by the shielding currents which are induced by the 4f magnetic moments in the superconducting CuO-lattice. The thermal expansion of GdBa2Cu3O7−δ shows a large peak at the ordering temperature of 2.2 K in both the superconducting and the nonsuperconducting samples.