Magnetization, Nernst effect and vorticity in the cuprates

Abstract Nernst and magnetization experiments reveal the existence of a large region of the cuprate phase diagram above the T c curve in which vorticity and weak diamagnetism exist without phase coherence. We discuss the implication that the transition at T c is caused by the loss of long-range phase coherence caused by spontaneous vortex creation. Below T c , these measurements provide an estimate of the depairing field H c 2 which is found to be very large ( 40 – 100 T depending on doping). We discuss the high-field Nernst and magnetization results, binding energy, and the phase diagram of hole-doped cuprates. Some new magnetization results on the vortex liquid in very underdoped LSCO in the limit T → 0 are reported as well.