Evidence for a temperature dependent anisotropy of the superconducting state parameters in underdoped SmBa2Cu3Ox

TL;DR

This study investigates how the anisotropy of superconducting parameters in underdoped SmBa2Cu3Ox varies with temperature, revealing a strong temperature dependence and minimal field influence, with implications for understanding high-temperature superconductivity.

Contribution

It provides the first detailed measurement of temperature-dependent anisotropy in underdoped SmBa2Cu3Ox using torque magnetometry, highlighting its strong temperature dependence.

Findings

Anisotropy strongly depends on temperature.

Weak dependence of anisotropy on magnetic field.

No evidence of field-dependent superfluid density.

Abstract

The temperature dependence of the anisotropy of the superconducting state parameters, {\gamma}, was studied by torque magnetometry for the high temperature superconductor SmBa2Cu3Ox in magnetic fields of up to 9 T. The measurements were performed on four underdoped single crystals with oxygen contents corresponding to Tc's varying from 42.8 to 63.6 K. The anisotropy was found to be strongly temperature dependent, while only a weak dependence on the magnetic field was observed. No evidence for a field dependent superfluid density was found. Possible origins of the temperature dependence of the anisotropy are discussed.