History effects and phase diagram near the lower critical point in YBa2Cu3O7 single crystals - art. no. 017006

Using a sensitive torque magnetometer we have studied magnetization curves for untwinned overdoped YBa2Cu3O7 single crystals in fields of up to 28 T. We demonstrate the existence of history effects below the lower critical po int and provide a full demarcation of the Bragg-glass phase. A pronounced s ymmetry is observed in the behavior of the phase lines, irreversible magnet ization, and value of the magnetization jump near both critical points.