Antiferromagnetism in CaCu${}_3$Ti${}_4$O${}_{12}$ studied by magnetic Raman spectroscopy

For CaCu${}_3$Ti${}_4$O${}_{12}$ – an insulator that exhibits a giant dielectric response above 100 K – Cu${}^{2+}$ antiferromagnetic spin ordering has been investigated by magnetic Raman scattering and magnetization measurements. Below the N'eel temperature, T${}_N=25$ K, magnetic excitations have been identified. Above T${}_N$ Raman spectra reveal short-range antiferromagnetic fluctuations that increase with cooling like T${}^{-1}$. No deviations from Curie-Weiss law have been observed above T${}_N$.