Complex spin structure and magnetic phase transition of Mn3−xFexSn alloys
W. Hanggai (Student TU Delft)
O. Hamutu (Student TU Delft)
G. A. De Wijs (Radboud Universiteit Nijmegen)
A.I. Dugulan (TU Delft - RID/TS/Instrumenten groep, TU Delft - RST/Fundamental Aspects of Materials and Energy)
N.H. van Dijk (TU Delft - RST/Fundamental Aspects of Materials and Energy)
E.H. Brück (TU Delft - RST/Fundamental Aspects of Materials and Energy)
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Abstract
The hexagonal Mn3−xFexSn compounds possess several desirable properties that make them suitable magnetocaloric materials, including a ferromagnetic (FM)-to-paramagnetic (PM) transition near room temperature and soft magnetic behavior. In this study, we use themelt-spinning technique to explore the Mn-Fe-Sn ternary system. By combining magnetization measurements,Mössbauer spectroscopy, neutron diffraction (ND), oriented powder x-ray diffraction, and density functional theory (DFT) calculation, the magnetocaloric effect, spin structures, and the intrinsic magnetic properties of polycrystallineMn3−xFexSn (x = 0.8 − 1.4) compounds are determined. The FM-to-PM transition temperature TC ranges from 253 K (x = 0.8) to 394 K (x = 1.4). At low temperature, a spin reorientation at TS is observed, where below TS a coexistence of FM order with spins along the c axis and antiferromagnetic order with spins within the a − b plane occurs for x = 0.8 and 1.0. However, for compounds with x = 1.2 and 1.4, only FM order with spins along the c axis has been found below TS. Above TS, the spin structure corresponds to FM order with spins aligned within the a − b plane for all compositions. The magnetic moments of Mn and Fe were evaluated using DFT, demonstrating good agreement with the ND results.
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