Influence of Paramagnetic Resonance on the Static Susceptibility. The Lattice—Bath Relaxation Time of Neodymium Ethyl Sulfate

Abstract

The spin—lattice—bath relaxation process of neodymium ethyl sulfate was investigated by measuring simultaneously the change in the static susceptibility and the microwave power absorbed at electron spin resonance. This technique can be used at constant temperature to distinguish the spin—lattice process from the lattice—bath process. The relaxation time of neodymium ethyl sulfate was studied at a microwave frequency of 14.5 GHz as a function of temperature, helium-exchange gas pressure, microwave power absorbed, two crystal orientations, and crystal size. At this microwave frequency the energy transfer from the lattice to the bath appears to be the rate-determining process. The dominant lattice—bath relaxation time, τp, is inversely proportional to the square of the bath temperature τpT2=0.20 sec·°K2 but is apparently independent of the crystal size, the helium-exchange gas pressure, and crystal orientation. The experimental data are in essential agreement with the data obtained by other researchers using different methods.