Superconductivity in rapidly quenched Mo-P-B alloys

Superconducting transition temperatures (T_c) were measured for a series of Mo-P-B alloys in the Mo-rich corner of the ternary system. The alloys were studied in two forms: (a) slowly cooled after induction melting, and (b) rapidly quenched in an arc hammer apparatus. The rapid quenching produced an amorphous structure, but most of the alloys also contained some crystalline material, indicating that this system is not conducive to easy glass formation. Ternary slowly cooled crystalline alloys in the concentration range 20 to 30 at % phosphorus and 10 to 20 at % boron had relatively highT_c values of 9.6 to 9.9 K; higher than for either the Mo-P or Mo-B binary systems.T_c values up to 9.02 K were observed for completely amorphous foils, consistent with the previously reported maximumT_c values for amorphous alloys in this system. This remains the highestT_c reported for a metallic glass. All of the rapidly quenched foils were brittle.