High-Field Superconductivity in Some bcc Ti-Mo and Nb-Zr Alloys

Zero electrical resistance at unusually high magnetic field strengths has been observed in the bcc alloys Ti-16 a/o (atomic percent) Mo, Nb-12 a/o Zr, and Nb-25 a/o Zr. The maximum high-field zero-resistance current density, Jc, in these alloys appears to be a sensitive function of temperature, the degree of cold-working, and the orientation of the applied transverse magnetic field. For cold-rolled alloy specimens in an applied transverse field, Jcis a maximum or minimum, according to whether the field is set respectively parallel or perpendicular to the rolled face of the specimen. In Ti-16 a/o Mo the zero-resistance condition is observed in fields at least a factor 35 greater than the bulk material critical field as inferred from calorimetric data.