Microwave spectroscopy in oxford: The first decade part II. Electron magnetic resonance

Abstract

Abstract Apparatus and techniques developed during World War Il for centimetre wavelengths included reflex klystrons as tuneable oscillators, improved silicon-tungsten point-contact diodes as detectors, together with waveguides and cavity resonators. Their use in experiments on microwave gas spectroscopy began in the Clarendon Laboratory early in 1945 (see Part I). In the autumn of the same year, experiments started there also on electron magnetic resonance, and are described here in Part 11. Ferromagnetic resonance in nickel metal was discovered by J. H. E. Griffiths (1946), and resonance measurements on single crystals of paramagnetic compounds were initiated by D. M. S. Bagguley in the autumn of 1946. These were extended to lower temperatures by Bleaney and Penrose, and the latter discovered hyperfine structure in a diluted compound of copper (Cu2+ 3d9) at Leiden in 1948 (Penrose, 1949). Study of the spectra of a wide range of compounds of the transition groups 3d, 4d and 5d, together with the lanthani...