Spin Dynamics of Rare Earth Ions in Phosphate Laser Glasses

TL;DR

This study investigates the spin dynamics of rare earth ions in phosphate glasses using 31P NMR, revealing phonon-mediated relaxation processes and inhomogeneous broadening effects across a range of temperatures.

Contribution

It introduces a model for analyzing NMR line broadening and correlation times in heavily doped phosphate glasses, providing new insights into spin relaxation mechanisms.

Findings

Correlation times range from 10^-2 to 10^-12 s between 4 K and 100 K

No evidence of spin-spin coupling among ions

Spin relaxation occurs via phonon processes, including Orbach process

Abstract

The spin dynamics of rare earth ions (Er, Nd, Sm and Gd) in heavily doped phosphate glasses have been investigated using 31P NMR. Correlation times in the range 10^-2 to 10^-12 s have been obtained for temperatures between 4 K and 100 K. No evidence of spin-spin coupling between the ions has been found and spin relaxation occurs via conventional phonon processes, including the Orbach process. A model involving inhomogeneous broadening of the NMR resonance lines, with distinct sample regions corresponding to the presence or absence of nuclear spin diffusion, has been used in extracting the electron spin correlation times from the NMR measurements.