An original noncontact measurement technique to determine the phase transition for the superconductor YBa2Cu3Ox is described. A piezoelectric is used to vibrate the sample normal to the superconductor surface, and a small coil which has a permanent magnet adhered to it, or an electromagnetic acoustic transducer (EMAT) for out-of-plane waves, is used to detect (by means of standard lock-in techniques) these vibrations, both on the Ohmic and the superconducting regimes as temperature is lowered. The magnitude of the induced voltage (by eddy currents) on the EMAT is plotted against temperature (T), and the changes in the conductivity in the Ohmic regime as well as during the superconducting transition (88.7<T<91.2K) are detected and compared to other more invasive methods. Furthermore, it is shown that the EMAT technique could allow us to explore the coupling between the net of vortex and the EMAT itself, well beyond the transition temperature, showing that the technique is promising to gather information on electron transport properties for fundamental studies or to provide reliable inspection into a production line.

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