Vortex phase diagram via magnetization measurements for H t c in Bi2Sr2CaCu2O8
1995; Elsevier BV; Volume: 246; Issue: 3-4 Linguagem: Inglês
10.1016/0921-4534(95)00152-2
ISSN1873-2143
AutoresYuji Yamaguchi, Nobuyuki Aoki, F. Iga, Yoshikazu Nishihara,
Tópico(s)High-pressure geophysics and materials
ResumoDC and AC magnetization for H t c-axis of an air-annealed Bi2Sr2CaCu2O8 single crystal have been investigated in detail. In a DC magnetization (M-H) curve above 30 K a distinct kink has been observed at Hk close to the irreversibility field (Hirr), where a distinct change also in AC loss (χ″) has been observed. Below 40 K a prominent second peak has been exhibited in the M-H curve. It has been shown that the field (Hm) at the maximum | dM / dH|, where the second grows rapidly, is almost temperature independent. The χ″ versus HDC curve has exhibited a sharp dip near the Hm. Also has been observed another characteristics field Ht, where a crossover in the magnetic relaxation occurs. These characteristics fields (Hk, Hm and Ht) give a well defined vortex phase diagram, which is discussed in relation to a flux-melting and a possible vortex/Bose glass transition.
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