Transition metals magnetic coupling

Since 1987 many exchange-coupled rare-earth-transition-metal magnets have been developed. Examples of exchange-coupled magnets are listed in table 2. 

A larger number of examples of 5f- 3d systems are known, and have been recently reviewed [43]. We reiterate here only the potentially enormously beneficial effect of sizable 5f-3d exchange couplings exploiting the large magnetic moments of first row transition metal ions and the anisotropy of actinides. Examples are the previously discussed U-Mn wheel and chain [36, 38]. 

In summary, NMR techniques based upon chemical shifts and dipolar or scalar couplings of spin-1/2 nuclei can provide structural information about bonding environments in semiconductor alloys, and more specifically the extent to which substitutions are completely random, partially or fully-ordered, or even bimodal. Semiconductor alloys containing magnetic ions, typically transition metal ions, have also been studied by spin-1/2 NMR here the often-large frequency shifts are due to the electron hyperfine interaction, and so examples of such studies will be discussed in Sect. 3.5. For alloys containing only quadrupolar nuclei as NMR probes, such as many of the III-V compounds, the nuclear quadrupole interaction will play an important and often dominant role, and can be used to investigate alloy disorder (Sect. 3.8). 

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