Spin glass freezing

The tSR data are compatible with either dense spin glass freezing or with the sudden condensation of a coherent Kondo state (for a discussion see, for example, Grewe and Steglich 1991) with slow, but dynamic spin correlations at 2.5K. The latter interpretation ties in with the specific heat data, especially in applied fields. The former could be explained in terms of the magnetic polaron model formulated by Kasuya et al. (1993a,b). 

Results of magnetic and heat-capacity measurements on amorphous Gdo 33Alog7 were reported by Coey et al. (1977). The temperature dependence of the magnetic susceptibility was found to exhibit a cusp-like shape characteristic of the spin glass freezing temperature. The temperature dependence of the specific heat C showed a... 

FC cooling the sample in a magnetic field T, spin-glass freezing temperature... 

Another subject class is concerned with diluted 4f metals. Sarkissian and Coles (1976) have tried to distinguish between spin-glass freezing and helical ordering in solid solutions of Gd, Tb and Dy in Y and Sc by means of resistivity and susceptibility measurements (fig. 12). These materials have attracted recent interest again, because some are candidates for anisotropic spin glasses (Baberschke et al. 1984). It also turned out that spin-glass behavior in yttrium based alloys occurs at much lower concentrations than previously claimed. 

The unique properties of STf(tv) described above are a challenge to get more insight into the dynamics of spin-glass freezing. At present, however, no theory is available to be compared with. Nevertheless the data already demonstrate the... 

Particularly valuable information on the dynamics of spin-glass freezing has recently been gained by experiments where both the real and imaginary component (x x") of the complex susceptibility x(T, co) have been measured accurate-... 

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