Observation of vortex lattice melting in large untwinned YBa$_2$Cu$_3$O$_{7-x}$ single crystals

TL;DR

This study investigates the vortex lattice melting in untwinned YBa₂Cu₃O₇₋ₓ crystals using muon spin rotation and neutron scattering, revealing a sharp first-order transition and its angular dependence.

Contribution

It provides the first combined muon spin rotation and neutron scattering analysis of vortex lattice melting in untwinned YBa₂Cu₃O₇₋ₓ crystals, highlighting the sharpness and angular dependence of the transition.

Findings

Vortex lattice melting occurs as a sharp first-order transition.

The melting temperature depends on the magnetic field angle.

Results align with thermal measurement data.

Abstract

We present a study of the vortex lattice in untwinned YBa$_2$Cu$_3$O$_{7-x}$ crystals, using a combination of muon spin rotation and neutron small angle scattering measurements. Both methods show a very sharp melting temperature consistent with a first order transition. The dependence of the melting temperature on the angle of the field with respect to the crystallographic c-axis is studied. The results are compared to thermal measurements.