FLUCTUATION EFFECT ON MAGNETIZATION AND SPECIFIC-HEAT IN HIGH-TEMPERATURE SUPERCONDUCTORS UNDER MAGNETIC-FIELD

Using the renormalized fluctuation theory developed to explain the resistive transition in high temperature superconductors (HTSC) under an applied field, a formula for temperature derivative of magnetization is derived which enables one to study the reversible temperature region in HTSC with layer structure. It is pointed out that, because of strong fluctuation effects in HTSC, the reversible dc magnetization of HTSC below T(cH) has a nontrival field dependent correction due to higher Landau level fluctuations to the usual mean field-like behavior, and that the linear temperature dependence should not be seen in BSCCO. A good agreement with YBCO data is obtained. A higher Landau level correction to the specific heat is also discussed.