Indirect Coupling of Nuclear Spins in Antiferromagnet with Particular Reference to MnF₂at Very Low Temperatures

Abstract

Indirect coupling of nuclear spins through hyperfine interaction with spin waves is discussed in the case of antiferromagnet at very low temperatures. The line width of the F19 nuclear magnetic resonance in MnF2 at 1.4° K observed by Shulman and Jaccarino (∼14 oe) proves to come mainly from this coupling. The line width of the Mn55 resonance in MnF2 is also evaluated to be about 600 oe.