Determination of hyperfine field distributions in amorphous magnets

• Published in: Journal of physics. Condensed matter 2006-08, Vol.18 (32), p.7751-7759, Article 7751
• Main Authors: Bentley, P M, Kilcoyne, S H
• Format: Article
• Language: English
• Subjects: Amorphous and quasicrystalline magnetic materials; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic properties and materials; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Mössbauer effect; other γ-ray spectroscopy; Physics; Studies of specific magnetic materials
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/18/32/022

We present an overview of two leading methods of determining probability distributions from Mössbauer spectra, using the model amorphous magnet Fe(80)B(20). A comparison is made between the maximum-entropy method, which permits analysis using truly arbitrary parameter probability distributions, and a Voigtian-based analysis, which uses a sum of Gaussian components to create parameter distributions of pseudo-arbitrary shape. Our results indicate that, in Fe(80)B(20), a Gaussian distribution of magnetic hyperfine fields is a very good approximation, although small deviations from a Gaussian shape are evident. We find that the apparent existence of correlations between the isomer shift and magnetic hyperfine field parameters, as found using Voigt-based analyses, may be an artefact of imposing a Gaussian shape on the parameter distributions. We conclude that maximum entropy and Voigtian analyses together provide a very powerful means of characterizing magnetic materials with Mössbauer spectroscopy.