Magnetic properties of the antiferromagnetic spin-1/2 chain system   $\beta$-TeVO$_{4}$
  The magnetic susceptibility and magnetization of high quality single crystal beta-TeVO4 are reported. We show that this compound, made of weakly coupled infinite chains of VO5 pyramids sharing corners, behaves as a S = 1/2 one-dimensional Heisenberg antiferromagnet. From magnetic experiments we deduce the intrachain antiferromagnetic coupling constant J/kB = 21.4 $\pm$ 0.2 K. Below 5 K a series of three phase transitions at 2.26, 3.28 and 4.65 K is observed. 
Yu. Savina, O. Bludov, V. Pashchenko, S.L. Gnatchenko, P. Lemmens and   H. Berger
cond-mat.str-el