Anisotropy in the vortex phase diagram and the pinning force density in the basal plane of YNi₂B₂C

Abstract

We present the magnetic field dependence of the critical current density from dc magnetization measurements concerning the anisotropic behaviour of flux line lattice (FLL) in a single crystal of YNi2B2C. The peak effect (PE) phenomenon is observed for all crystallographic orientations, but the second magnetization peak (SMP) anomaly is observed only for H∥a. Our study reveals that the FLL obtained when H∥[110] is better ordered within the basal plane. However, the FLL for H∥c is found to be even more ordered than that for H∥[110]. The perfect square symmetry of the FLL for H∥c is perhaps responsible for promoting the realization of the best spatial order of the FLL prior to the onset of the PE, indicating a correlation between the crystalline lattice and the vortex lattice. We have also found a change over in the power law governing the decay of the critical current density which is identified as a crossover from weak to weaker pinning regime in the phase diagram.