Spin glass order parameter in RE40Y23Cu37 amorphous alloys (RE = rare earth)

Quantum relaxation in the low-temperature magnetic susceptibility of the amorphous alloya−Tb2Fe

“…Above T f , Ј follows Curie's law and ЉϷ0. Both components Ј and Љ have an acute maximum, similar to that of a spin glass or to the one shown by other random anisotropy materials 11 at temperatures T f Ј and T f Љ , respectively, which increase as the exciting frequency increases. The onset of a nonzero Љ is due to magnetic relaxation processes with characteristic relaxation times of the order of exp , i.e., the same mechanism which gives rise to the difference between the ZFC and FC magnetization curves.…”

Specific Heat of Dy.40 Cu.37 Y.23 Amorphous Alloy at Low Temperatures

“…; Values of C m for this alloy are shown in Figure 3 as C m versus T. This excess specific heats have been attributed to the magnetic effects in this magnetic alloy. It is clear that C m shows clearly broad maximum centered at T m =28±1 K. The value of T m is about 1.1 times higher than the value of T sg (=23.5 K) _ obtained from the low field ac susceptibility results (del Moral et al,1986). Values of C m /T versus T are shown in Figure 4.…”

“…This investigation showed the spin glass nature for x<0.35 for Gd. The magnetic amorphous Dy 0.40 Cu 0.37 Y 0.23 alloy exhibits low cusp in its low field ac susceptibility as shown in Figure 1, indicating spin glass phase transition to the paramagnetic phase (del Moral et al,1986). Theoretical calculations of Debye temperature, lattice specific heat and the spin glass ordering temperatures in the magnetic RE 0.33 Cu 0.67 , RE 0.33 Al 0.67 and RE 0.33 Ag 0.67 amorphous alloys have been reported (Mohammed et al, 1994).…”