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Mar 20 – 23, 2023
Campus Garching
Europe/Berlin timezone

Magnetic phase transitions in frustrated epsilon-Fe$_2$O$_3$ polymorph

Mar 20, 2023, 4:00 PM
Yards 4 - 6 (Fakultät für Maschinenwesen)

Yards 4 - 6

Fakultät für Maschinenwesen

Board: MO-069
Poster Magnetism, Superconductivity, Topological Systems, Magnetic Thin Films an other electronic phenomena Poster Session MONDAY


Prof. Jose Luis Garcia-Muñoz (Institut de Ciència de Materials de Barcelona (ICMAB-CSIC))


The epsilon phase of Fe$_2$O$_3$ (ε-Fe$_2$O$_3$) presents captivating properties and it is receiving extraordinary attention due to its great application potentials. It stands out for its huge coercive field (up to 2 T at room temperature), millimeter-wave ferromagnetic resonance, remarkable non-linear magneto-optical effect, magneto-electric coupling [1], and room temperature ferroelectricity [2]. It has been much less studied than other iron (III) oxides because its formation requires special conditions [1].
ε-Fe$_2$O$_3$ presents a complex noncentrosymmetric structure (Pna2$_1$) with three distinct octahedral and one tetrahedral environments for Fe sites. We present a neutron-based investigation on the rich magnetic phase diagram and properties of geometrically frustrated ε-Fe$_2$O$_3$ nanoparticles. The nature of the incommensurate magnetic order, attributed by some authors to a spiral ground state [5], was investigated in zero and applied magnetic fields, and reinterpreted in the light of the models confronted to neutron data [6]. The study illustrates the interplay between the huge magnetic anisotropy, frustration and the stabilization of the super-hard ferrimagnetic phase in the 150-500 K interval.

[1] M. Gich et al., Nanotech. 17, 687 (2006).
[2] M. Gich et al., Adv. Mater. 26 (2014) 4645.
[3] J. A. Sans et al. Nature Comms (2018), 9, 4554.
[4] J.L. García-Muñoz et al., Chem. Mater. 29, 9705 (2017)
[5] Yu. V. Knyazev et al. Phys. Rev.B 101, 094408 (2020).
[6] A. Romaguera et al., submitted

Primary authors

Dr Arnau Romaguera (Institut de Ciència de Materials de Barcelona (ICMAB-CSIC)) Ms Naureen Khanam (Institut de Ciència de Materials de Barcelona (ICMAB-CSIC)) Dr Zheng Ma (Institut de Ciència de Materials de Barcelona (ICMAB-CSIC)) Dr Javier Herrero-Martín (CELLS-ALBA Synchrotron) Dr J. Alberto Rodríguez-Velamazán (Institut Laue-Langevin) Dr Martí Gich (Institut de Ciència de Materials de Barcelona (ICMAB-CSIC)) Prof. Jose Luis Garcia-Muñoz (Institut de Ciència de Materials de Barcelona (ICMAB-CSIC))

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