Other
Scientific paper
Aug 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993georl..20.1671o&link_type=abstract
Geophysical Research Letters (ISSN 0094-8276), vol. 20, no. 16, p. 1671-1674.
Other
150
Crystal Structure, Magnetite, Oxidation, Phase Transformations, Spinel, Transition Temperature, Electrical Resistivity, Rocks, Sediments, Soils
Scientific paper
It has long been believed that magnetic remanence and susceptibility would change markedly at T(V) in the case of coarse grains but only slightly or inappreciably in the case of fine grains. We find on the contrary that remanence changes at T(V) by 50-80 percent in both large and small crystals, if they are stoichiometric. However, minor surface oxidation suppresses the transition, and the fact that fine grains oxidize more readily leads to an apparent size dependence. Our experiments used submicron magnetite cubes with mean sizes of 0.037, 0.076, 0.10 and 0.22 micron which were initially nonstoichiometric. A saturation isothermal remanent magnetization (SIRM) given in a 2.5 T field at 5 K decreased steadily during zero-field warming to 300 K with little or no indication of the Verwey transition. After the oxidized surface of each crystal was reduced to stoichiometric magnetite, the SIRM decreased sharply during warming by 50-80 percent around 110 K. The change in SIRM for the 0.22-micron grains was almost identical to that measured for a 1.5 mm natural magnetite crystal. Thus a 10 exp 12 change in particle volume does not materially affect the remanence transition at T(V) but oxidation to z = 0.3 essentially suppresses the transition.
Dunlop David J.
Moskowitz Bruce M.
Özdemir Özden
No associations
LandOfFree
The effect of oxidation on the Verwey transition in magnetite does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The effect of oxidation on the Verwey transition in magnetite, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The effect of oxidation on the Verwey transition in magnetite will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1492152