# Site Specific Knight Shift Measurements of the Dilute Kondo lattice System Ce$_{1-x}$La$_x$CoIn$_5$

## TL;DR

This study uses site-specific NMR measurements to explore how La dilution affects the electronic and magnetic properties of the Ce$_{1-x}$La$_x$CoIn$_5$ Kondo lattice, revealing inhomogeneity and persistent quantum critical fluctuations.

## Contribution

It provides detailed NMR analysis of site-dependent Knight shifts and relaxation rates, uncovering spatial inhomogeneity and quantum criticality in a dilute Kondo lattice.

## Key findings

- Heavy electron coherence diminishes with La dilution.
- Antiferromagnetic fluctuations are suppressed near La sites.
- Quantum critical fluctuations persist up to 75% dilution.

## Abstract

$^{115}$In Nuclear magnetic resonance data are presented for a series of Ce$_{1-x}$La$_x$CoIn$_5$ crystals with different La dilutions, $x$. Multiple In(1) sites associated with different numbers of nearest-neighbor cerium atoms exhibit different Knight shifts and spin lattice relaxation rates. Analysis of the temperature dependence of these sites reveals both an evolution of the heavy electron coherence as a function of dilution, as well as spatial inhomogeneity associated with a complete suppression of antiferromagnetic fluctuations in the vicinity of the La sites. Quantum critical fluctuations persist within disconnected Ce clusters with dilution levels up to 75%, despite the fact that specific heat shows Fermi liquid behavior in dilute samples.