Giant magnetostriction inBi2Sr2CaCu2O8single crystal in the superconducting state and its mechanism

Abstract

Unusually large magnetostriction for a superconductor was found in a single crystal of the high-${\mathit{T}}_{\mathit{c}}$ cuprate ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{8}$. The sample length change was measured along the ab plane under magnetic fields applied up to 6 T parallel to the c axis. The sample decreased in length during the field increasing process and with relative change exceeding ${10}^{\mathrm{\ensuremath{-}}4}$ at 4.8 K. A quantitative model has been proposed which accounts for the magnetostriction in terms of internal forces arising from flux pinning. These observations show that magnetostriction measurement is a novel and unique technique to investigate the pinning effect and related phenomena in type-II superconductors.