Magneto-Optical Studies of Magnetic Field Dependence of Spin-Lattice Relaxation

摘要

A magneto-optical technique was developed to measure the spin-lattice relaxation time of paramagnetic ions in a crystal lattice as a function of applied static magnetic field strength. This method utilized the Faraday effect at low temperatures. An ac magnetic field modulated the Faraday rotation of plane polarized light traversing the sample. The phase angle between the diamagnetic rotation and the total rotation was measured as a function of frequency of the modulating magnetic field. When the frequency of modulating field exceeded the inverse spin-lattice relaxation time, the modulation of the light due to paramagnetic contributions was diminished leaving only the modulation due to diamagnetic contributions. From these measurements the spin-lattice relaxation time was determined. Second order effects were also considered for the case where tau was assumed to have a time-varying component. (Author)