Canted antiferromagnetism in high-purity NaFeF3 prepared by a novel wet-chemical synthesis method

We report a synthesis method, and structural and magnetic characterization, for 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 ($\ensuremath{\theta}$) of \ensuremath{-}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 supports that weak ferromagnetism is inherent to ${\mathrm{NaFeF}}_{3}$ and not due to an impurity. From powder neutron diffraction data, we describe the magnetic structure precisely as a weakly canted G-type (magnetic space group $P{n}^{\ensuremath{'}}m{a}^{\ensuremath{'}}$). A ferromagnetic component is allowed in $P{n}^{\ensuremath{'}}m{a}^{\ensuremath{'}}$, however, this component is too small to be confirmed on the basis of powder neutron diffraction data and may be absent in zero magnetic fields.