Influence of magnetic impurities on the heat capacity of nuclear spins
Dyugaev A.M., Ovchinnikov Yu.N., and Fulde P.
It is found that in a wide range of temperatures and magnetic fields even a small concentration of magnetic impurities in a sample leads to a T~' temperature dependence of the nuclear heat capacity. This effect is related to a nuclear-spin polarization by the magnetic impurities. The parameter that controls the theory turns, out not to be the impurity concentration nimp but instead the quantity nxmpMc/ι where μβ and μη are the magnetic moments of an electron and a nucleus, respectively. The ratio of με and μη is of order of 103. PACS: 72.15.ея