Superconducting properties of RuSr2GdCu2O8 studied by SQUID magnetometry

TL;DR

This study investigates the magnetic properties of RuSr2GdCu2O8 using SQUID magnetometry, revealing that observed peaks are due to flux motion during measurement rather than intrinsic superconducting properties.

Contribution

It demonstrates that magnetization peaks in Ru-1212 are caused by flux motion, not intrinsic features, and provides tests to distinguish measurement artifacts from true material properties.

Findings

Magnetization peaks are due to flux motion, not intrinsic superconductivity.

Impurities like Sr2GdRuO6 do not cause the observed peaks.

Proposed tests can differentiate measurement artifacts from true properties.

Abstract

For polycrystalline RuSr2GdCu2O8 (Ru-1212), distinct peaks have been reported in d.c. magnetization in the superconducting state of the sample. Sr2GdRuO6 (Sr-2116), the precursor for the preparation of Ru-1212, shows similar peaks in the same temperature regime. Based on measurements performed on both bulk and powdered samples of Ru-1212 and Sr-2116, we exclude the possibility, that the observed behavior of the magnetization of Ru-1212 is due to Sr-2116 impurities. The effect is related to the superconductivity of Ru-1212, but it is not an intrinsic property of this compound. We provide evidence that the observation of magnetization peaks in the superconducting state of Ru-1212 is due to flux motion generated by the movement of the sample in an inhomogeneous field, during the measurement in the SQUID magnetometer. We propose several tests, that help to decide, whether the features observed in a SQUID magnetization measurement of Ru-1212 represent a property of the compound or not.