Magnetic susceptibility rare earth elements

Pseudo-contact shifts can arise only in systems where the magnetic susceptibility of the paramagnetic center is anisotropic. This interaction appears to be dominant in certain transition-metal ions (Co ), as well as such rare-earth elements US Dy , Er +, and Yb. The chemi( shift from the dipo-... 

In the 1980s, reports from Corbett s and Simon s laboratories presented a then-new chemistry based on interstitially stabilized clusters of zirconium and the rare-earth elements. " Coincident with those discoveries, molecular orbital schemes were offered to aid in understanding the electronic factors that exert influence on the stability of these cluster-based compounds. Nevertheless, direct physical measurements that supported the schemes were relatively scarce, and were almost entirely restricted to magnetic susceptibilities. " " ... 

The group of J.P. Costes was the first to report on the use of rare-earth ions as the anisotropic source to design single-chain magnet systems [75]. Slow relaxation of the magnetization was observed in a Cu VTb heterometal-lic complex unfortunately not structurally characterized but formulated (LCu)2Tb(N03) on the basis of elemental analysis (with H3L 2-hydroxy-M- 2-[2-hydroxyethyl-amino]ethyl benzamide). Frequency dependence of the ac susceptibility was observed below 5 K (for frequencies ranging from 1 to 1000 Hz). From these data, the relaxation time of the magnetization was extracted and found to follow an activated behavior with = 28.5 K and... 

Fig. 6. Generalized susceptibility functions /(f) for Y, Dy, and Gd showing the pronounced maxima in Dy and Y corresponding to the occurrence of incommensurate magnetic order. Alloys of Gd (see e.g., Wenger 1986) or other rare earths with Y show incommensurate order similar to Dy. The ripples in the Gd function are ascribed to matrix element instaUlities. (After Liu et al. 1971.)...

Here, Jac is the exchange coupling between states of the rare-earth ion and those of the Cu02 planes with local susceptibility x((u), M is the dipole transition-matrix element of the corresponding CEF transition, and = k T. The local magnetic susceptibility (Becker et al. 1977) is defined as... 

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