Magnetic-field tuned anisotropy in superconducting Rb(x)Fe(2-y)Se(2)

TL;DR

This study investigates the anisotropic superconducting properties of Rb(x)Fe(2-y)Se(2), revealing unusual field-dependent anisotropy possibly linked to coexisting antiferromagnetic order.

Contribution

It provides new insights into the magnetic anisotropy behavior in RbFeSe superconductors, highlighting its field dependence and potential magnetic interactions.

Findings

Anisotropy is temperature independent in the superconducting state.

Anisotropy strongly depends on the magnetic field.

Large zero-temperature magnetic penetration depth observed.

Abstract

The anisotropic superconducting properties of a Rb(x)Fe(2-y)Se(2) single crystal with transition temperature 32 K were investigated by means of SQUID and torque magnetometry, probing the effective magnetic penetration depth and the magnetic penetration depth anisotropy. Interestingly, the anisotropy is found to be temperature independent in the superconducting state, but strongly field dependent. This unusual anisotropic behavior, together with a large zero-temperature effective magnetic penetration depth is possibly related to a superconducting state heavily biased by the coexisting antiferromagnetic phase.