Magnetic-field-induced reorientation in the spin-density-wave and the spin-stripe phases of the frustrated spin-1/2 chain compound beta-TeVO4

beta-TeVO4 is a frustrated spin-1/2 zig-zag chain system, where spin-density-wave (SDW), vector-chiral (VC) and an exotic dynamic spin-stripe phase compete at low temperatures. Here we use torque magnetometry to study the anisotropy of these phases in magnetic fields of up to 5 T. Our results show that the magnetic-field-induced spin reorientation occurs in the SDW and in the spin-stripe phases for mu H-0 >= 2 T. The observed spin reorientation is another element of the anisotropic phase diagram for the field directions in the ac and a*b crystallographic planes. The presented results should help establishing the model of anisotropic magnetic interactions, which are responsible for the formation of complex magnetic phases in beta-TeVO4 and similar low-dimensional quantum spin systems.