Magnetic Properties of Melt-Processed YBa2Cu3O7-δ Crystals
The critical current of melt-grown Y-Ba-Cu-O materials has been investigated by magnetic measurements. The melt-grown YBa2Cu3O7-δ crystals are c-axis oriented and have no high-angle grain boundaries. The size of Y2BaCuO5 inclusions is reduced by the addition of a small amount of Pt and by the increase in the content of Y2BaCuO5 phase. The critical current density of the materials is improved by the reduction of the size. Some Y2BaCuO5 precipitates in Pt-added samples are needle shaped. Some materials show enhancement of the critical current density at medium external fields. The peak is depressed by the oxygen annealing of the materials. The peak field depends on the temperature. These samples don’t show any unusual enhancement of magnetic relaxation around the peak field, as reported for Bi2Sr2CaCuO8 single crystals.
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