SINGLE VORTEX-SHELL PENETRATION IN MESOSCOPIC VORTEX MATTER

M. I. DOLZ; Y. FASANO; N. R. CEJAS BOLECEK; H. PASTORIZA; M. KNOCZKYKOWSKI; C. J. VAN DER BEEK

Buenos Aires

Conferencia; Poster presentation en la conferencia Low Temperatures 27 (LT27)); 2014

IUPAP, Departamento de Física, UBA e Instituto de Física Conicet

We investigated features of flux penetration and configurational changes in mesoscopic vortex matter by means of AC and DC micro-Hall sensor measurements in freestanding Bi2Sr2CaCu2O8+δ micron-sized disks. We show that oscillations in the AC magnetic transmittivity and local magnetization in the system with less than hundred vortices are evidence of the configurational changes associated to the discretized entrance of vortices on increasing field. We are able to detect the entrance of a single vortex-shell at the edge of the samples by means of high-resolution frequency-dependent measurements. This result is also supported by the detection of the same phenomena with quantitative agreement in micron-sized Bi2Sr2CaCu2O8+δ samples with variable geometry. The dissapearence of these oscillations on increasing vortex density is associated to the discrete-to-continuum crossover of flux penetration in mesoscopic vortex matter.