Nuclear Magnetic Relaxation in Antiferromagnetics, II

Abstract

Theory of nuclear magnetic relaxation in antiferromagnetics treated in the preceding paper for non-magnetic ions is extended to the case of magnetic ions. Strong hyperfine interactions and quadrupole interactions are the distinctive feature of the problem. The line width and the relaxation rate are calculated by using the spin wave approximation at low temperatures and the model of Gaussian random modulation at high temperatures. Order estimations of T1 and T2 are made for several substances, which predict that the nuclear resonance will be difficult to detect above the Curie point because of the broadening due to the hyperfine interaction, while the resonance will become detectable at sufficiently low temperatures where the low frequency components of the local field spectra decrease remarkably. The effects of the quadrupole interaction are also discussed.