Previous magnetization-vector measurements on a YBa2Cu3O7-δ crystal, tilted by angles (θ) of up to 90° relative to the fixed field applied initially along the c axis during cooling to 4.2 K, have revealed that the original trapped vortices along c develop sizeable branches in the ab planes. These measurements have now been extended on the same crystal to tilt angles of up to 180°, and it is found that Bab, the flux density component along ab, reverses in sign and reaches a large negative maximum near θ = 135°, despite the positive orientation of the internal field along ab. This anomalous behavior of Bab is attributed to the entry of antivortices that form branches antiparallel to the original vortex branches along ab as a consequence of strongly attractive antivortex-vortex interactions. The varying coexistence of antivortex and vortex branches is seen to be reversible as θ is cycled between 90° and 180°.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering