New insights for the description of magnetic correlations inferred from μSR

13th International Conference on Muon Spin Rotation, Relaxation and Resonance

De Réotier, P. Dalmas^1,2 ; Yaouanc, A.^1,2 ; Maisuradze, A.^3,4,5

University Grenoble Alpes, INAC-SPSMS, Grenoble

F-38000, France^1

CEA, INAC-SPSMS, Grenoble

F-38000, France^2

Department of Physics, Tbilisi State University, Chavchavadze 3, Tbilisi

GE-0128, Georgia^3

Physik-Institut der Universität Zürich, Zürich

CH-8057, Switzerland^4

Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institute, Villigen-PSI

CH-5232, Switzerland^5

关键词: Coherence lengths;    Long range magnetic order;    Longitudinal fields;    Magnetic correlation;    Reverse Monte Carlo;    Short-range correlations;    Static polarization;    Strong collisions;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/551/1/012005/pdf
DOI  :  10.1088/1742-6596/551/1/012005

来源: IOP

【 摘 要 】

Whenever a compound exhibits a spontaneous μSR 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 μSR 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.