Structural and magnetic characterization of the elusive Jahn-Teller active NaCrF3

Abstract

We report on the structural and magnetic properties of the elusive Jahn-Teller active compound NaCrF3, for first time synthesized in large quantities allowing detailed characterization. The crystal structure of NaCrF3 is initially described from a DFT model, which helped serve as the basis for indexing and structure determination confirmed by high-resolution synchrotron x-ray diffraction experiments. NaCrF3 adopts the triclinic space group P¯1 (isostructural with NaCuF3). Magnetometry studies at low temperature show that NaCrF3 is a weak antiferromagnet, Weiss temperature θ=−4 K. The Néel temperature is TN=21.3 K and the paramagnetic moment μ=4.47μB is in accordance with the theoretical S=2. Field-dependent measurements between 2 and 12 K unveil the onset of metamagnetic behavior. Our experiments revealed a weakly canted A-type magnetic structure observed by neutron powder diffraction, with a magnetic propagation vector (1/2,1/2,0) and a magnetic moment of 3.51μB at 1.5 K. Our results shed further light on the Jahn-Teller effects and strong correlations as a function of A-ion size in the family ACrF3.