Evidence for a smooth superconductor to normal state transition for nonzero applied magnetic field in Sr0.9La0.1CuO2

TL;DR

This study demonstrates that in Sr0.9La0.1CuO2, the transition from superconducting to normal state under magnetic fields is smooth due to a finite size effect, with magnetization data collapsing onto a universal curve.

Contribution

The paper provides experimental evidence for a magnetic field induced finite size effect causing a smooth transition in a cuprate superconductor, supported by magnetization data analysis.

Findings

Magnetization data consistent with finite size scaling near transition

Transition is smooth under nonzero magnetic fields due to correlation length limitations

Pressure has negligible effect on the critical temperature Tc

Abstract

We present and analyze field cooled magnetization data, revealing for 0<H<5 T remarkable consistency with a magnetic field induced finite size effect. It is traced back to the fact that the correlation length gsi cannot grow beyond the limiting length scale LH set by the magnetic field, where at temperature Tp(H), gsi(T) = LH. Thus, in sufficiently homogeneous samples and nonzero H the transition from the superconducting to the normal state turns out to be smooth and the appropriately scaled magnetization data fall near Tp(H) on a universal curve. Consistent with the generic behavior of optimally doped cuprates we also show that the pressure effect on Tc is negligibly small, while the negative value of the relative volume change mirrors that of the ansisotropy.