In-Plane Angular Effect of Magnetoresistance of Quasi-One-Dimensional Organic Metals, (DMET)2AuBr2 and (TMTSF)2ClO4

Harukazu YOSHINO, Kazuya SAITO, Hiroyuki NISHIKAWA, Koichi KIKUCHI, Keiji KOBAYASHI and Isao IKEMOTO

Comparative study is presented for the in-plane angular effect of magnetoresistance of quasi-one-dimensional organic conductors, (DMET)2AuBr2 and (TMTSF)2ClO4. 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)2AuBr2 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)2I3. Weak anomaly was detected for the magnetoresistance of (TMTSF)2ClO4 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.
(J. Phys. Soc. Jpn., 66, 2410-2418 (1997))

Anomalous Angular Dependence of Magnetoresistance of an Organic Superconductor, (DMET)2I3


Angular dependence of magnetoresistance of a quasi-one-dimensional organic superconductor, (DMET)2I3 has been measured at 4.2 K for magnetic field up to 7.0 T. For the field of 1.0 T, the angular dependence of the magnetoresistance is smooth over the entire range of angles, reflecting the quasi-one-dimensional band structure of the salt. When the magnetic field of 7.0 T was rotated in the most conducting ab plane, the magnetoresistance for the current along both the b- and c*-axes showed discontinuous changes in its slope at the angles of +-15 deg. from the most conducting axis. The anomaly occuring at 7.0 T is considered to be due to a change in electronic state induced by the magnetic field almost perpendicular to the quasi-1D Fermi surface.
(J. Phys. Soc. Jpn., 64, 2307-2310 (1995))

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