Abstract
Nuclear magnetic resonance studies on Mn55 in α- and β-Mn metals have been made by both the steady and the pulse methods.
Nuclear spin-lattice relaxation time T1 and spin-spin relaxation time T2 were measured by the pulse method in the temperature range of 1.5°K to 77°K. The measured value of T1T of β-Mn keeps a constant value of 7 m sec °K through the temperature range measured. Using both the T1T value and the Knight shift, the origin of the effective magnetic field acting on a nucleus in a Mn metal was concerned. T2 of 0.1 m sec. was observed to be temperature independent.
Several nuclear spin-lattice relaxation mechanisms together with the origin of the effective magnetic field in the Mn metal are discussed. T1 due to the dipole, quadrupole, and orbital interactions is calculated using free electron approximation in which the electronic wave function includes partly p- or d-character. It is shown that the orbital interaction is more effective than those due to the dipole or quadrupole interaction.
Mn55 nuclear magnetic resonance in an antiferromagnetic α-Mn metal was observed by the pulse method in zero external magnetic field and at temperatures of 1.5°K to 4.2°K.
