# High and low-temperature crystal and magnetic structures of epsilon-Fe2O3 and their correlation to its magnetic properties

**Authors:** M. Gich, C. Frontera, A. Roig, E. Taboada, E. Molins, H. R. Rechenberg, J. D. Ardisson, W. A. A. Macedo, C. Ritter, V. Hardy, J. Sort, V. Skumryev, J. Nogues  
**arXiv:** [cond-mat/0604677](https://arxiv.org/abs/cond-mat/0604677)  
**Date:** 2006-04-28  
**Summary page:** https://www.summarizepaper.com/en/paper/cond-mat--0604677v1/

## Key points

- Crystal and magnetic structures of orthorhombic e-Fe2O3 studied
- Rietveld refinement, Mossbauer spectroscopy, magnetization measurements, and heat capacity measurements used for analysis
- Above 150 K, e-Fe2O3 exhibits collinear ferrimagnetism with magnetic moments aligned along the a axis
- Below 80 K, different magnetic ordering observed with square-wave incommensurate structure
- Transition between states identified as second-order phase transition
- Structural changes affecting coordination of tetrahedral and one octahedral Fe sites responsible for transformation
- Findings discussed in relation to temperature dependence of e-Fe2O3's magnetic properties
- Study provides insights into crystal and magnetic structures of e-Fe2O3 and potential applications in magnetism and materials science.

## Summary

The crystal and magnetic structures of the orthorhombic e-Fe2O3 have been extensively investigated in this study. The researchers employed simultaneous Rietveld refinement of X-ray and neutron powder diffraction data, along with Mossbauer spectroscopy, magnetization measurements, and heat capacity measurements to gain a comprehensive understanding of the material's properties. The results reveal that at temperatures above 150 K, the e-Fe2O3 polymorph exhibits collinear ferrimagnetism, with the magnetic moments aligned along the a axis. However, below 80 K, a different magnetic ordering is observed characterized by a square-wave incommensurate structure. This transition between the two states is identified as a second-order phase transition. Further analysis indicates that subtle structural changes primarily affecting the coordination of the tetrahedral and one of the octahedral Fe sites are responsible for this transformation. The researchers discuss these findings in relation to the temperature dependence of e-Fe2O3's magnetic properties. Overall, this study provides valuable insights into both the crystal and magnetic structures of e-Fe2O3 which contribute to our understanding of its behavior at different temperatures and lays the groundwork for potential applications in various fields such as magnetism and materials science.