THERMAL-EXPANSION ANOMALY IN AMORPHOUS Y-FE SPIN-GLASSES

The thermal expansion anomaly in amorphous Y100-xFex (70 less-than-or- equal-to x less-than-or-equal-to 92.5) alloys has been measured with a differential transformer-type dilatometer. A large thermal expansion anomaly is observed in spite of the absence of ferromagnetism, and its magnitude is as large as that of amorphous Lu-Fe alloys which exhibit a re-entrant spin-glass behavior. This clearly indicates that the mag netovolume effect is not necessarily correlated with the appearance of ferromagnetism. The large negative electronic contribution to the the rmal expansion coefficient of amorphous Y-Fe alloys is similar to that of Fe-based Fe-Ni alloys. Such a characteristic property is explained by taking into account the amplitude of the local moment.