Lattice anomalies and magnetic excitations of the spin web compound Cu3TeO6

Abstract

We report on the magnetic susceptibility and Raman scattering measurements of the S = 1/2 three-dimensional (3D) spin web compound Cu3TeO6. The magnetic susceptibility shows an antiferromagnetic ordering at T-N similar to 61 K and a deviation from the Curie-Weisslaw around 150 K. Raman spectra show the emergence of a new mode at 132 cm(-1) for temperatures below T * similar to 50 K (approximate to 0.8 T-N). At the same temperature, phonon anomalies in intensity and frequency show up. This gives evidence of pronounced magneto-elastic effects. In addition, we observe a two-magnon Raman spectrum around 214 cm(-1). Compared to typical 3D spin systems, its robust temperature dependence suggests that a frustrated spin topology with a reduced spin coordination number also enhances spin-phonon couplings.