Symmetry change in the angular dependence of magnetoresistance of the two-dimensional organic conductor, τ-(EDO-S, S-DMEDT-TTF)2(AuBr2)(AuBr2)y, (y∼0.75)

Angular dependence of magnetoresistivity, rho(c)(phi), of a quasi-two-dimensional organic conductor, tau-(EDO-S, S-DMEDT-TTF)(2)(AuBr2)(AuBr2)(y), (y similar to 0.75), where EDO-S, S-DMEDT-TTF is ethylenedioxy-S, S-dimethylethylenedithio-tetrathiafulvalene was measured for the magnetic field and the electrical current parallel and perpendicular to the most conducting ab plane. The magnetoresistance is negative in the semiconducting range below about 50 K. It was found that the period of rho(c)(phi) changes from 90 degrees at 5.0 T to 180 degrees at 0.5 T and the principal axis of rho(c)(Q) at 0.5 T depends on the field-orientation at 5.0 T. The change in the period and the principal axis of rho(c)(phi) is discussed in terms of formation and reorientation of magnetic domains.