HR: 10:50h
AN: V41E-03 [PDF]
TI: Direct Magnetic Measurements at High Pressures
AU: LeGoff, M
EM: legoff@ipgp.jussieu.fr
AF: Institut de Physique du Globe, Laboratoire de Paleomagnetisme, 4 place Jussieu, Paris, 75252
France
AU: * Gilder, S A
EM: gilder@ipgp.jussieu.fr
AF: Institut de Physique du Globe, Laboratoire de Paleomagnetisme, 4 place Jussieu, Paris, 75252
France
AU: Chervin, J
EM: JClaude.Chervin@pmc.jussieu.fr
AF: Universite Pierre et Marie Curie, Physique des Milieux Condens‚s, 2 place Jussieu, Paris, 75252
France
AU: Peyronneau, J
EM: peyronno@ipgp.jussieu.fr
AF: Institut de Physique du Globe, Laboratoire de Paleomagnetisme, 4 place Jussieu, Paris, 75252
France
AB:
Direct magnetic measurements of extremely small sample volumes at high pressure are difficult, primarily because of
interference from the high magnetizations of the pressure vessels. For this reason, we developed a "non-magnetic"
beryllium-copper, membrane-type diamond cell that houses a system designed to measure the reversible magnetic susceptibility
of micron-sized samples under pressures in excess of 30 GPa. Our system employs two unequal pick up coils wound in opposition
around a diamond resulting in a virtually null magnetic surface. Around these is an inducing coil, mounted in null mutual
inductance. A lock-in amplifier measures the output of the sensing coil. The cell and detection system are placed in the
confines of an electromagnet. Thus the pressure of the cell is remotely controlled and the ac (reversible) susceptibility
(Xrev) is measured as a function of applied field (H), with H varying from -1.2 T to +1.2 T. Because the integral of
Xrev(H)dH is proportional to the magnetic moment (of the reversible part of the remanence, or Mrev), we can measure the
reversible hysteresis parameters of ferromagnetic materials as a function of pressure. Example measurements and details of
the method will be presented.
DE: 1519 Magnetic mineralogy and petrology
DE: 3924 High-pressure behavior
DE: 3994 Instruments and techniques
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting