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Magnetization, vortex state and specific heat in the superconducting state of RuSr2GdCu2O8

“…Measuring the volume susceptibility of a stationary Ru1212 sample in a home-made SQUID system, 15 we were led to the conclusion, that measurements in magnetometers that do not necessitate sample movement would lead to the revelation of a universal behavior in the superconducting state of Ru1212 for samples of comparable quality. New experimental and software options, not available for our previous investigations, 12,13,14,15,16 allow us in the present paper to extend this discussion and provide experimental evidence that strongly supports this point of view. Additionally, we briefly describe how the magnetic-field homogeneity in a commercial SQUID system can be improved and combined with small scan lengths to give artifact-free measurements similar to those on a stationary sample.…”

“…13,14,16 Here, we will expand this discussion and we will provide experimental evidence that (i) the magnitude of magnetic-field inhomogeneities in the superconducting magnet of the magnetometer that leads to artifacts below T c is smaller than 0.2 Oe, (ii) the reported different behaviors in the dc magnetization measurements of Ru1212 below T c could be the result of different magnetic-field profiles in the magnet.…”

“…13,14,16 We were able to avoid sample movement in a home-made magnetometer. 15 These measurements 15 will serve as a reference for comparison in the present study.…”

“…In a series of investigations, 12,13,14,15,16 we have tried to determine the origin of the reported different behaviors in the dc magnetization measurements of Ru1212 below T c . We attributed them to artifacts arising from the movement of the sample in an inhomogeneous magnetic field during the measurement in the Superconducting Quantum Interference Device (SQUID) magnetometer.…”

Towards universal magnetization curves in the superconducting state ofRuSr2GdCu2OPapageorgiou1, Braun2, Görlach3 et al. 2003Phys. Rev. B102100View full textAdd to dashboardCite

“…Nevertheless, these measurements showed several suspicious "symptoms": among others, the observed features below T c were insensitive (not reversed) to a field reversal and also, contrary to the resistivity and ac susceptibility measurements, they were not reproducible for the same sample. In our previous works 26,35 we have shown that Ru-1212Gd is sensitive to field inhomogeneities in the SQUID's superconducting magnet that can create artifacts in its measured magnetic moment below T c . This problem is related to the procedure of the measurement (movement of the sample within a pick up coil system) and the assumptions under which the magnetometer's software calculates the magnetic moment from the SQUID response to the movement of the sample.…”