TUNNEL-DIODE OSCILLATOR APPLICATION TO HIGH-SENSITIVITY DE-HAAS-VAN-ALPHEN AND SUPERCONDUCTING CRITICAL-FIELD STUDIES OF ANISOTROPIC ORGANIC CONDUCTORS

We report the first application of a tunnel diode circuit to investigate the de Haas-van Alphen effect and superconducting critical field values in small single crystal organic conductors. The materials of interest are in the family of charge transfer salts (BEDT-TTF)2X, where X is one of a number of anion structures. Small (less-than-or-equal-to 1 mm3) oriented single crystal samples were placed inside the inductance coil of the LC tank circuit of the oscillator, and measurements were carried out at low temperatures and in high magnetic fields. We observe a marked improvement over previous magnetic methods for the determination of both de Haas-val Alphen signals and for critical field studies. The method is applicable where such information is required for very small samples.