A partially successful attempt has been made to measure the magnetic moment per unit volume of ferromagnetic materials as a function of pressure to the 100-kbar region. The apparatus, an early version of which has been described previously, consists basically of two opposed Bridgman flat anvils of alumina. One anvil also acts as a dielectric-filled microwave resonant cavity for an x-band spectrometer, allowing electron spin resonance studies to be made to high pressure. The sample to be studied is placed in contact with the anvil-cavity and covered with a pressure-transmitting medium which in turn is encircled by a flat pyrophyllite gasket. Indium has proven to be the most suitable pressure transmitting medium. This system consistently performs well to pressures above the Bi I-II transition (26 kbar) and somewhat less reliably to pressures about the Bi III-V transition (76 kbar). Bismuth transitions are used as calibration points.
(c) 1968 American Institue of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics and may be found at http://link.aip.org/link/?JAPIAU/39/2152/1;