Whenever a compound exhibits a spontaneous muSR oscillation, long-range magnetic ordering is usually inferred. Here we show that some caution is required. The coherence length needs not to be large for a spontaneous muon spin precession to be observed. Establishing the incommensurate nature of a magnetic structure, solely based on muSR measurements, may not be reliable. The absence of a spontaneous muon precession at low temperature does not mean that the system under investigation does not display long-range magnetic ordering. The relaxation measured in zero and longitudinal field in the quasi-static limit is usually analyzed in the framework of the strong-collision model, the static polarization function being taken to be the famous Kubo-Toyabe function. This might not be satisfactory if short-range correlation effects are strong. Here we propose a method based on the maximum entropy concept and reverse Monte Carlo technique which gives results consistent with those obtained in 2013 by analytical means for the considered example.
@article{arxiv.1410.2767,
title = {New insights for the description of magnetic correlations inferred from muSR},
author = {P. Dalmas de Reotier and A. Yaouanc and A. Maisuradze},
journal= {arXiv preprint arXiv:1410.2767},
year = {2014}
}
Comments
To appear in the proceedings of the 13th International Conference on Muon Spin Rotation, Relaxation and Resonance, Grindelwald, Switzerland, 1-6 June 2014