Marc Beranger

High resolution low field ESR spectrometer

Abstract Organic conductors and semi-conductors are extensively studied usually by high field ESR Spectrometry. Higher resolution and choice criteria for materials used in earth-field magnetometers can be provided by low-field ESR experiments. In the spectrometer described, the sample is placed in a Bloch configuration where the rf measurement axis, the rf excitation axis and the dc field (1,8 MHZ) axis are orthogonal. The minimum detectable field in the detection coil is 10−14T. All the spectrometer is automatized. Typical results concerning three classes of known organic radicals which are good candidates for magnetometry are presented.