One-dimensional spin chains in NaCuFe${}_2$(VO${}_4$)${}_3$ studied by high-frequency ESR and static magnetization

We report magnetization and high-frequency electron spin resonance spectroscopy data (HF-ESR) on the metal oxide NaCuFe${}_2$(VO${}_4$)${}_3$. The magnetically active ions Fe${}^{3+}$ and Cu${}^{2+}$ in this compound form quasi-one-dimensional spin chains. Magnetization data confirm the evolution of long-range antiferromagnetic order below T${}_N$ = 9.3 $\pm$ 0.4 K. At high temperatures, the data imply a Curie-Weiss-like behaviour with the Weiss temperature $\Theta$ $\approx$ 81.2 K. However, no AFM resonances are observed at low temperatures. Instead, the HF-ESR spectra show a single broad resonance feature without sizeable zero-field splitting. Upon heating, this resonance shifts to a smaller g-factor associated with Fe${}^{3+}$-spins. Based on the these data, the AFM ordered phase of the compound will be discussed.