Magnetic torque study of the temperature dependent anisotropy parameter in overdoped superconducting single-crystal YBa_2Cu_3O_7

Abstract

An overdoped YBa2Cu3O7 single crystal was studied by SQUID and torque magnetometry in order to investigate the temperature dependence of the anisotropy parameter close to the transition temperature T_c (0.87 T_c < T < T_c). Angle dependent torque measurements were performed and analyzed with the widely used Kogan model [Phys. Rev. B 38, 7049 (1988)] as well as with an extended model by Hao and Clem [Phys. Rev. Lett. 67, 2371 (1991)], taking into account the influence of the vortex cores on the magnetization. Both approaches yield similar results, with an out-of-plane anisotropy parameter around 6.5 which slightly increases with decreasing temperature, and a temperature independent in-plane anisotropy parameter gamma_ab}= 1.12(5).

7 pages, 6 figures, version2 - accepted for publication in PRB

References in corpus (10)

• Observation of Fermi-surface-dependent nodeless superconducting gaps in Ba0.6K0.4Fe2As2
• Multiple Nodeless Superconducting Gaps in (Ba0.6K0.4)Fe2As2 Superconductor from Angle-Resolved Photoemission Spectroscopy
• Evidence for complex order parameter in La_{1.83}Sr_{0.17}CuO_4
• Point-Contact Spectroscopy of Iron-Based Layered Superconductor LaO${}_{0.9}$F${}_{0.1-\delta }$FeAs
• Universal observation of multiple order parameters in cuprate superconductors
• Nodal Superconductivity with Multiple Gaps in SmFeAsO${}_{0.9}$F${}_{0.1}$
• Anisotropy of superconducting single crystal SmFeAsO_(0.8)F_(0.2) studied by torque magnetometry
• Evidence for two distinct anisotropies in the oxypnictide superconductors SmFeAsO_(0.8)F_(0.2) and NdFeAsO_(0.8)F_(0.2)
• Anisotropy of the superconducting state parameters and intrinsic pinning in low-level Pr-doped YBa2Cu3O(7-delta) single crystals
• Evidence for a temperature dependent anisotropy of the superconducting state parameters in underdoped SmBa2Cu3Ox