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Critical behavior in tetragonal antiperovskite GeNFe3 with a frustrated ferromagnetic state
1Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China. bswang@issp.ac.cn whsong@issp.ac.cn.
Physical Chemistry Chemical Physics : PCCP
|May 13, 2017
Summary
Tetragonal GeNFe3 exhibits a ferromagnetic to paramagnetic transition at 76 K. Critical exponents suggest dominant long-range magnetic coupling, influenced by competing iron electronic states and N-Fe covalent bonds.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Magnetism
Background:
- Tetragonal GeNFe3 displays a second-order ferromagnetic (FM) to paramagnetic transition at 76 K.
- The material retains tetragonal symmetry below 550 K, with a frustrated ground FM state.
Purpose of the Study:
- Investigate the critical behavior and magnetic coupling in tetragonal GeNFe3.
- Determine the dominant theoretical model governing magnetic interactions.
Main Methods:
- Variable temperature X-ray diffraction to confirm structural symmetry.
- Bulk magnetization studies to analyze critical phenomena.
- Analysis of critical exponents using modified Arrott plot, Kouvel-Fisher method, and critical isotherm analysis.
Main Results:
- Critical exponents consistently indicate dominant long-range magnetic coupling, aligning with the mean-field (MF) theoretical model.
- Experimental magnetization-temperature-magnetic field (M-T-H) data exhibit scaling behavior, supporting the MF model.
- The estimated exchange distance J(r) ~ r^-4.8 falls between MF and short-range 3D Heisenberg models.
Conclusions:
- The critical behavior in GeNFe3 is driven by a balance between local iron magnetic moments and itinerant N-Fe covalent bonding.
- The findings provide insights into the complex magnetic interactions in frustrated magnetic materials.
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