The effect of oxygenation and annealing on the peak effect of the magnetization of melt-grown YBa/sub 2/CU/sub 3/O/sub 7-/spl delta//
The influence of oxygenation and high temperature annealing on the peak effect of the magnetization of melt-grown YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (0</spl delta/<1) material has been studied. A control sample was prepared using a normal melt-growth procedure and oxygenated during cooling. A single grain cut from the control sample was annealed in the temperature region of the crystal growth (1030/spl deg/C-900/spl deg/C) followed by a standard oxygenation. Some of the control sample was powdered and oxygenated for different lengths of time. The peak of the magnetization shifted to a higher field for the sample oxygenated for longer times. Compared with the control sample, the peak of the magnetization of the sample annealed in the higher temperature region shifted to a lower field. The results are discussed within the framework of the collective pinning and collective creep model.