# Determination of the nature of fluctuations using $^8Li$ and $^9Li$ $\beta$-NMR and spin-lattice relaxation

## TL;DR

This study uses $eta$-NMR and spin-lattice relaxation measurements of $^8Li$ and $^9Li$ in Pt and SrTiO$_{3}$ to distinguish magnetic from electric quadrupolar relaxation mechanisms, revealing insights into local environmental fluctuations.

## Contribution

It provides a comparative analysis of relaxation rates for $^8Li$ and $^9Li$ to identify the dominant relaxation mechanisms in different materials.

## Key findings

- In Pt, relaxation ratio close to magnetic limit suggests magnetic fluctuations dominate.
- In SrTiO$_{3}$, ratio indicates electric quadrupolar relaxation is significant.
- Results enhance understanding of local fluctuation dynamics in $eta$-NMR studies.

## Abstract

We report a comparison of the $1/T_1$ spin lattice relaxation rates (SLR) for $^9Li$ and $^8Li$ in Pt and SrTiO$_{3}$, in order to differentiate between magnetic and electric quadrupolar relaxation mechanisms. In Pt, the ratio of the $1/T_{1}$ spin relaxation rates $R_{Pt}$ was found to be 6.82(29), which is close to but less than the theoretical limit of $\sim7.68$ for pure magnetic relaxation. In SrTiO$_{3}$ this ratio was found to be 2.7(3), which is close but larger than the theoretical limit of $\sim2.14$ expected for pure electric quadrupolar relaxation. These results bring new insight into the nature of the fluctuations in the local environment of implanted $^8Li$ observed by $\beta$-NMR.