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Updated: Jun 3, 2026

Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
First-order phase transitions in CaFe₂As₂ single crystal: a local probe study
M Alzamora1, J Munevar, E Baggio-Saitovitch
1Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150, Urca, Rio de Janeiro, RJ, Brazil.
Abstract:
(57)Fe Mössbauer spectroscopy has been used to investigate the structural and magnetic phase transitions of CaFe₂As₂ (T(N) = 173 K) single crystals. For this compound we found that V(ZZ) is positive and parallel to the c-axis of the tetragonal structure. For CaFe₂As₂ a magnetic hyperfine field B(hf) was observed at the (57)Fe nucleus below T(N) ~173 K. Analysis of the temperature dependence of B(hf) data using the Bean-Rodbell model shows that the Fe spins undergo a first-order magnetic transition at ~173 K. A collinear antiferromagnetic structure is established below this temperature with the Fe spin lying in the (a, b) plane. Below T(N) the paramagnetic fraction of Fe decreases down to 150 K and for lower temperatures all the Fe spins are magnetically ordered.
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