We describe a range of techniques developed by the Oxford group for use in conjunction with the Millimeter-wave Vector Network Analyzer in measurements of magnetic resonance and high-frequency conductivity, at extremely low temperatures and high magnetic fields. Included are a variety of resonant cavity techniques. The cylindrical geometry is used to produce high-Q tunable cavities, ideally suited to measurements of the frequency and temperature dependence of, for example, cyclotron resonance of carriers in GaAs- (Ga,Al)As heterojunctions. A family of rectangular cavities has been designed specifically for measurements of the angle-dependent high-frequency conductivity of organic molecular metals; these systems allow us either to rotate the whole cavity in the external magnetic field, thus measuring the dependence of a particular component of the conductivity tensor on magnetic field orientation, or to rotate the sample within the cavity, thus measuring different components of the magneto-conductivity. We also describe a non-resonant measurement using a pressure cell with optical access permitting experiments at up to 1.8 GPa. Examples of data obtained from each technique are included.

Date Published: 9 September 1999
PDF: 14 pages
Proc. SPIE 3828, Terahertz Spectroscopy and Applications II, (9 September 1999); doi: 10.1117/12.361033

Published in SPIE Proceedings Vol. 3828:
Terahertz Spectroscopy and Applications II
J. Martyn Chamberlain, Editor(s)