Phase Transition from Crossing Lattice to Tilted Lattice Near ab-plane in Bi_(2)Sr_(2)CaCu_(2)O_(8+delta) Single Crystal

摘要

The vortex phases in the high-quality Bi_(2)Sr_(2)CaCu_(2)O_(8+delta) single crystal have been studied by means of the local ac-magnetic permeability measurements by using the miniature coils. The structural transition has been indicated in the vortex solid phase, where the linear dependence of the 1~(st) order vortex melting phase transition H_(c)~(m)(H_(ab)), a fingerprint of the crossing lattice, sharply changes its character, and separates the strong pinning pancake-vortex phase from the weak pinning phase. The phase transition from the crossing lattice to the tilted vortex lattice near the ab-plane is suggested.