Sign change of the vortex Hall effect in superconducting YBCO thin films with a square pattern of ion-irradiated defect columns

• Published in: Physica. C, Superconductivity Superconductivity, 2017-02, Vol.533, p.144-147
• Main Authors: Zechner, G., Haag, L.T., Lang, W., Dosmailov, M., Bodea, M.A., Pedarnig, J.D.
• Format: Article
• Language: English
• Subjects: Critical current (superconductivity); Critical temperature; Crystallography; Electric potential; Flux pinning; Hall effect; High temperature; High temperature superconductors; Irradiation; Magnetic flux; Matching; Order parameters; Pinning; Superconductivity; Superconductors; Temperature; Thin films; Vortex Hall effect; Vortex matching; Vortices; YBCO superconductors
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/j.physc.2016.06.001

•A square array of artificial defects with 300 nm spacing was fabricated in a YBCO film to periodically modulate the superconducting order parameter.•Ion beam irradiation with a non-contact, pre-fabricated mask was used to create the defect columns.•Strong vortex matching effects were observed in the critical current.•A novel vortex matching effect in the transverse Hall voltage was found that includes a sign change of the Hall coefficient.•The vortex Hall matching effect is interpreted by enhanced pinning of vortices in commensurate arrangements with the defect column array. The Hall effect in the mixed state of thin films of the high-temperature superconductor YBa2Cu3O7−δ (YBCO) that were patterned with a square array of regions with suppressed superconducting order parameter is investigated. Cylindrical defect columns penetrating the entire thin YBCO film along its crystallographic c−axis have been created by irradiation with He+ ions through a silicon stencil mask. Distinct peaks of the critical current at commensurate arrangements of magnetic flux quanta with the artificial defect lattice confirm enhanced vortex pinning. Vortex motion not only leads to a dissipative voltage along the current direction but also to a transverse voltage, termed vortex Hall effect. We report on the observation of a novel commensurability effect in the transverse Hall signal. A sign change and a positive peak of the Hall coefficient appear in a narrow magnetic field range around the matching field. The feature appears in the temperature range below the critical temperature, where the Hall effect usually is negative in underdoped and optimally-doped cuprate superconductors. The results indicate that the Hall matching effect originates from enhanced pinning of the vortices along the regular defect columns.