DETECTION OF SUPERCONDUCTING TRANSITIONS BY MAGNETICALLY MODULATED ELECTRICAL RESISTANCE

A new technique for detecting superconductivity, based on observing the effect of magnetic field modulation on the dc resistance of superconductors, is presented. The phase detected response to the magnetic modulation shows a peak at Tc for both metallic and ceramic superconductors, analogous to that observed in magnetically modulated microwave absorption. The results further demonstrate that the magnetically modulated microwave absorption peak at Tc is not equivalent to the non-resonant low field microwave absorption observed in the ceramic superconductors.