Mechanism of broadened superconducting transition in oxides

The field-enhanced broadening of the superconducting transition has been noticed as the unique properties of the high Tc cuprate superconductors. A model is proposed to assume the situation of dynamical mixing of the microscopic superconducting and normal regions. The model is similar to the fluctuation model but assumes the extreme case to occur in the two dimensional superconductor in the high temperature region. The predicted superconducting volume fraction is compared with the experimentally observed significant broadening of the transition in single-crystalline (La1-xSrx)2CuO4 (LSCO) to give a semi-quantitative agreement