MAGNETOSTRICTION OF HTSC SINGLE-CRYSTALS

We have measured the sample length change of HTSC single crystals in t he superconducting state in a magnetic field. The magnetic field was a pplied parallel to the crystalline c-axis direction and was swept at a constant rate of 10 mT/s up to 6 T. The sample length change was meas ured along the ab-plane direction, i.e., perpendicular to the field. W e have found for the Bi2Sr2CaCu2O8 single crystals that the relative s ample length change (DELTAL/L) is extraordinarily large for a supercon ductor, on the order of 10(-4). For the case of (La1-xSrx)2CuO4, the a mount of magnetostriction was not as large as for the Bi system, but t he magnetostriction curves had many similarities. For both compounds, a relaxation phenomenon was observed when the field sweep was suspende d at a certain field value. These observations are discussed in relati on to flux line pinning.