Skip to main content
placeholder image

Peak-effect and angular hysteresis in Jc(H, ��) dependencies for YBa2Cu3O7-�� epitaxial films

Conference Paper


Abstract


  • New phenomena - peak-effect and angular hysteresis - in field/angle J c(H, ��) dependencies are detected for YBCO epitaxial films at moderate dc magnetic fields H parallel to the film. Films (300-350 nm thick) are deposited by off-axis dc magnetron sputtering onto rcut sapphire substrate buffered with CeO2. Surface roughness (peak-to-valley) determined by AFM does not exceed 2 nm. Jc(H, ��)-curves are measured by low-frequency ac magnetic susceptibility and four-probe transport technique. Jc(H) at Hab-plane for the most smooth films reveal dome-shape enhancement of Jc(up to 10 p.c.) above Jc(0) value, starting from the field H* ascribed to the first critical field H c1 of thin film. Jc(H)-plots at Hc-axis with a plateau at low fields followed by monotonic fall-down are consistent to our model of vortex lattice depinning from the out-of-plane linear defect network (growth-induced edge dislocations). Field dependencies of Jc at arbitrary inclination angles may be recalculated from Jc(H, ��0) and Jc(H, ����/2), assuming independent effects of normal Hcos�� and parallel Hsin�� field components on Jc. Angle Jc(��)- dependencies evolution with H is shown to be consistent with dominant mechanism of pinning on edge dislocations. The most surprizing feature of this evolution is emergence of the peak in Jc(��)-dependence for Hc-direction, becoming observable only above threshold magnetic field Hp dependent on film thickness and surface roughness. Angular hysteresis in Jc(H, ��) dependence is detected for magnetic field directions close to Hab-plane. This hysteresis is sensitive to magnetic/angular pre-history and together with observed peak-effect at Hab-plane can be understood by account for surface (and/or geometrical) barrier as additional pinning source for Abrikosov vortices. �� 2006 IOP Publishing Ltd.

Publication Date


  • 2006

Citation


  • Pan, V. M., Pozigun, S. A., Cherpak, Y. V., Komashko, V. A., Kasatkin, A. L., Pashitskii, E. A., . . . Pan, A. V. (2006). Peak-effect and angular hysteresis in Jc(H, ��) dependencies for YBa2Cu3O7-�� epitaxial films. In Journal of Physics: Conference Series Vol. 43 (pp. 674-677). doi:10.1088/1742-6596/43/1/165

Scopus Eid


  • 2-s2.0-33746282425

Start Page


  • 674

End Page


  • 677

Volume


  • 43

Issue


  • 1

Place Of Publication


Abstract


  • New phenomena - peak-effect and angular hysteresis - in field/angle J c(H, ��) dependencies are detected for YBCO epitaxial films at moderate dc magnetic fields H parallel to the film. Films (300-350 nm thick) are deposited by off-axis dc magnetron sputtering onto rcut sapphire substrate buffered with CeO2. Surface roughness (peak-to-valley) determined by AFM does not exceed 2 nm. Jc(H, ��)-curves are measured by low-frequency ac magnetic susceptibility and four-probe transport technique. Jc(H) at Hab-plane for the most smooth films reveal dome-shape enhancement of Jc(up to 10 p.c.) above Jc(0) value, starting from the field H* ascribed to the first critical field H c1 of thin film. Jc(H)-plots at Hc-axis with a plateau at low fields followed by monotonic fall-down are consistent to our model of vortex lattice depinning from the out-of-plane linear defect network (growth-induced edge dislocations). Field dependencies of Jc at arbitrary inclination angles may be recalculated from Jc(H, ��0) and Jc(H, ����/2), assuming independent effects of normal Hcos�� and parallel Hsin�� field components on Jc. Angle Jc(��)- dependencies evolution with H is shown to be consistent with dominant mechanism of pinning on edge dislocations. The most surprizing feature of this evolution is emergence of the peak in Jc(��)-dependence for Hc-direction, becoming observable only above threshold magnetic field Hp dependent on film thickness and surface roughness. Angular hysteresis in Jc(H, ��) dependence is detected for magnetic field directions close to Hab-plane. This hysteresis is sensitive to magnetic/angular pre-history and together with observed peak-effect at Hab-plane can be understood by account for surface (and/or geometrical) barrier as additional pinning source for Abrikosov vortices. �� 2006 IOP Publishing Ltd.

Publication Date


  • 2006

Citation


  • Pan, V. M., Pozigun, S. A., Cherpak, Y. V., Komashko, V. A., Kasatkin, A. L., Pashitskii, E. A., . . . Pan, A. V. (2006). Peak-effect and angular hysteresis in Jc(H, ��) dependencies for YBa2Cu3O7-�� epitaxial films. In Journal of Physics: Conference Series Vol. 43 (pp. 674-677). doi:10.1088/1742-6596/43/1/165

Scopus Eid


  • 2-s2.0-33746282425

Start Page


  • 674

End Page


  • 677

Volume


  • 43

Issue


  • 1

Place Of Publication