Cooling-Induced Phase Transition in Amorphous CoCrZr Alloy

In amorphous Co sub 77 Cr sub 11.7 Zr sub 11.3 ribbons, produced by melt spinning, irreversible changes of hysteresis magnetic properties and Curie temperature were observed after thermal cycling (TC) (300-78-300K). After TC the coercive force H sub c increased by 35%, magnetization B sub s at the magnetic field 4.5 Oe by 6%, and remanent magnetization B sub r by 3%. Maturing of thermal-cycled samples at 300K during 10 h led to the further increasing of H sub c , B sub s and B sub r by 60, 16, and 10%, respectively, as compared with the as-cast state. Subsequent TC changed neither H sub c nor B sub s and B sub r , After maturing of as-cast ribbons at 300K for four weeks H sub c became larger by 55%. The observed dependencies are explained as a sequence of phase transitions in the amorphous state connected with metastable high-temperature modification of cobalt-based local order after quenching.