YBa2Cu3O7−δ: Enhancing jc by Field Orientation
Transport properties of dense, pressed pellets of field-oriented grains of YBa2Cu3O7−δ have been studied in the superconducting phase (T=77K) as a function of current, annealing time, and magnetic field. These pellets have strikingly different annealing properties from similarly prepared but unoriented samples. The oriented samples show significant enhancements in density and degree of orientation and transport j c with length of annealing time. The best samples have less than 2% of the x-ray intensity corresponding to misoriented grains, and a density so high that excess low-T oxygen annealing is required for the best j c (currently, j c (77K) > 1500A/cm2). These values are limited by the magnetic field generated by the current itself.
KeywordsCritical Current Magnetic Field Dependence Contact Resistivity Oriented Sample Josephson Effect
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