Investigation of high T c superconductors by means of torque measurements

We have calculated and experimentally determined on two samples of YBa ₂Cu ₃O _7-δ the torque due to the shape anisotropy in a magnetic field. Furthermore we observed in rotating fields losses which are obviously connected with the existence of superconductivity. This effect provides further informations as well as the possibility to detect small volumes of superconducting material.