Angular dependence of the first-order vortex-lattice phase transition in Bi2Sr2CaCu2O8

Abstract

The paramagnetic peak in the local ac susceptibility χ′ is used to identify the first-order vortex-lattice phase transition in Bi2Sr2CaCu2O8 at various tilt angles θ of the dc magnetic field with respect to the c-axis. The transition field Hm follows roughly the 2D scaling function Hdc cos(θ). The amplitude of the paramagnetic peak, and thus the jump in magnetization ΔB, do not depend on the tilt angle which demonstrates that the entropy jump at the transition, ΔS, is insensitive to the presence of the in-plane field.