Magnetovolume effects in Zr(Fesub(1-x)Cosub(x))2

The thermal expansion and forced volume magnetostriction of Zr(Fesub(1-x)Cosub(x))2 have been measured. The results indicate that the magnetovolume coupling between spontaneous volume magnetostriction and spontaneous magnetisation is very large and is almost independent of the concentration of Co in the ferromagnetic region (i.e. for x = 0.0 to 0.4). Furthermore, an extraordinarily large negative thermal expansion at low temperatures and a large forced volume magnetostriction at 4.2 K have been observed in the ferromagnetic compound with x = 0.4, both of which are comparable in magnitude to those observed in Fe-Ni Invar alloys. Fairly large forced volume magnetostriction, which does not vary linearly with the applied field, has been observed in mictomagnetic compounds with x = 0.5 and 0.6. This phenomenon has been explained by use of a simple model in which the volume change is ascribed to the change in the polarisation of the 3d band. (author)