Magnetism and electronic dynamics in $CuCr_{2-x}Sn_xS_4$ spinels studied by transferred hyperfine fields at $^{119}Sn$ and muon spin rotation and relaxation

TL;DR

This study explores the magnetic and electronic properties of Sn-doped CuCr2S4 spinels using muon spin rotation and Mössbauer spectroscopy, revealing complex magnetic transitions and inhomogeneous spin dynamics.

Contribution

It provides new insights into the magnetic ground state and spin dynamics of Sn-substituted CuCr2S4, highlighting the effects of doping on magnetic transitions and local magnetic environments.

Findings

Identification of low-temperature magnetic transitions at 80 K and 40 K.

Observation of inhomogeneous broadening indicating spin disorder above 80 K.

Differences in hyperfine spectra due to probe positions and magnetic coupling.

Abstract

We investigated magnetization, muon spin rotation ($\mu$SR), and $^{119}Sn$ M\"{o}ssbauer spectroscopy on Sn substituted $CuCr_{2-x}Sn_xS_4$ (x=0.03 and 0.08) spinel compounds. The magnetization and $\mu$SR results reveal similar additional low-temperature magnetic transitions around 80 K and 40 K as found for the undoped material, indicating a magnetic ground state deviating from a simple collinear ferromagnet. The observed changes in the M\"{o}ssbauer hyperfine spectra are less pronounced and are discussed in view of the different positions of the local probes $\mu^+$ and $^{119}Sn$ and their different magnetic coupling to the magnetic Cr lattice. Above 80 K, both $\mu$SR and M\"{o}ssbauer spectra show temperature-dependent inhomogeneous broadening either due to structural or charge disorder and changing spin dynamics that can be related to a precursor magnetic phase above the well-defined static low-temperature phase.