In-Plane Angular Effect of Magnetoresistance of Quasi-One-Dimensional Organic Metals, (DMET)_<b>2</b>AuBr_<b>2</b>and (TMTSF)_<b>2</b>ClO_<b>4</b>

Abstract

Comparative study is presented for the in-plane angular effect of magnetoresistance of quasi-one-dimensional organic conductors, (DMET) 2 AuBr 2 and (TMTSF) 2 ClO 4 . The magnetoresistance for the magnetic and electrical fields parallel and perpendicular to the most conducting plane, respectively, was measured at 4.2 K and up to 7.0 T. (DMET) 2 AuBr 2 shows an anomalous hump in the field-orientation dependence of the magnetoresistance for the magnetic field nearly parallel to the most conducting axis and this is very similar to what previously reported for (DMET) 2 I 3 . Weak anomaly was detected for the magnetoresistance of (TMTSF) 2 ClO 4 in the Relaxed state, while no anomaly was observed in the SDW phase in the Quenched state. By comparing the numerical angular derivatives of the magnetoresistance, it is shown that the anomaly in the in-plane angular effect continuously develops from zero magnetic field and is closely related to the quasi-one-dimensional Fermi surface. A simple method is proposed to estimate the anisotropy of the transfer integral from the width of the hump anomaly.