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arXiv · 2006.12891

Canted antiferromagnetism in high purity $\mathrm{NaFeF_3}$ prepared by a novel wet-chemical synthesis method

Fabian L. M. Bernal·Bruno Gonano·Fredrik Lundvall·David S. Wragg·Helmer Fjellvåg·Fabien Veillon·Wojciech A. Sławiński·Øystein S. Fjellvåg
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Abstract

We report a novel synthesis method for, and structural and magnetic characterization of the fluoroperovskite $\mathrm{NaFeF_3}$. We have developed a wet-chemical method that allows preparation of large volumes of air-sensitive fluoroperovskites with high purity. $\mathrm{NaFeF_3}$ has a N\'eel temperature ($T_N$) of 90 K and a Weiss constant ($\theta$) of -124 K, corresponding to dominant antiferromagnetic interactions. Below $T_N$, a slight difference is observed between zero-field and field cooled samples, indicating spin-canting and weak ferromagnetism. AC magnetometry confirms that weak ferromagnetism is inherent to $\mathrm{NaFeF_3}$ and not due to impurities. From powder neutron diffraction data, we describe the magnetic structure precisely as a weakly canted G-type (magnetic space group $Pn'ma'$). A ferromagnetic component is allowed in $Pn'ma'$, however, this component may be absent in zero magnetic fields and is too small to be confirmed on the basis of powder neutron diffraction data.

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Fabian L. M. Bernal, Bruno Gonano, Fredrik Lundvall, David S. Wragg, Helmer Fjellvåg, Fabien Veillon, Wojciech A. Sławiński, Øystein S. Fjellvåg. 2020-06-23. Canted antiferromagnetism in high purity $\mathrm{NaFeF_3}$ prepared by a novel wet-chemical synthesis method. https://doi.org/10.1103/physrevmaterials.4.114412

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