Observation of a first-order phase transition deep within the vortex-solid region of YBa2Cu3O7
arXiv:1003.4688 · doi:10.1088/0953-2048/24/10/105019
Abstract
We have investigated the magnetic phase diagram of a fully oxygenated detwinned YBa2Cu3O7 single crystal by means of magneto-caloric and magnetization measurements, and found thermodynamic evidence for a temperature dependent first-order phase-transition line deep within the vortex-solid region. The associated discontinuities in the entropy are apparently proportional to the magnetic flux density, which may hint at a structural transition of the vortex lattice.