Evidence for Magnetism in the Low-Temperature Charge-Density-Wave Phase of NbSe3

Experimental data on the transverse magnetoresistance in Nb${\mathrm{Se}}_3$, in the temperature range from 1 to 59 K, in magnetic fields of up to 227 kG, and for a variety of electrical currents are presented. They constitute clear evidence that (1) the observed behavior is caused neither exclusively by the normal galvanomagnetic properties of the conduction electrons nor by the conduction properties of the sliding charge-density wave and (2) the low-temperature phase of Nb${\mathrm{Se}}_3$ is not, as it is ordinarily thought, a simple charge-density wave but exhibits a strong magnetic field dependence. The most probable structure of that phase is a mixed density wave, involving charge- and spin-density characteristics as well as a net magnetization.