Canted antiferromagnetism in high purity $\mathrm{NaFe}{\mathrm{F}}_3$ prepared by a novel wet-chemical synthesis method

Abstract

We report a novel synthesis method for, and structural and magnetic characterization of the fluoroperovskite $\mathrm{NaFe}{\mathrm{F}}_3$. We have developed a wet-chemical method that allows preparation of large volumes of air-sensitive fluoroperovskites with high purity. $\mathrm{NaFe}{\mathrm{F}}_3$ has a Néel 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 $\mathrm{NaFe}{\mathrm{F}}_3$ 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 $P{n}^{\prime }m{a}^{\prime }$). A ferromagnetic component is allowed in $P{n}^{\prime }m{a}^{\prime }$, 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.

9 pages, 10 figures