Astronomy and Astrophysics – Astronomy
Scientific paper
Mar 1999
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999geoji.136..505z&link_type=abstract
Geophysical Journal International, Volume 136, Issue 3, pp. 505-518.
Astronomy and Astrophysics
Astronomy
2
Hysteresis Parameters, Rock Magnetism, Small Particles, Thermoremanence, Titanomagnetites
Scientific paper
Hysteresis properties were measured as a function of grain size for milled and afterwards annealed or etched synthetic 1-125 μm Fe2.3Ti0.7O4 (TM70) spinel particles. In general, there is a notable alteration of magnetic parameters by annealing or etching that marks a change of internal stresses caused by dislocations. From the results of remanent coercive force Hcr versus grain size D on a log-log scale for annealed particles, a relation Hcr~D-m, m~0.60, can be derived in the whole size range, which parallels an analogous law found earlier for the coercive force Hc. However, from the ratio Hcr/Hc versus D on a semi-log scale, a transitional region is seen at D approximately 30-70 μm from the bending curve that possibly marks a transition from pseudo-single domain (PSD) to multidomain (MD) behaviour. For 14.5 and 37.5 μm particles, Hc data as a function of temperature between room temperature and the Curie point at approximately 110°C show a marked maximum at approximately 70°C that appears to be primarily a property of TM70, although there is evidently also an effect due to the microcrystalline structure. A curve of saturation remanent magnetization Irs versus temperature T shows a steady decrease for rising T with Irs becoming zero at approximately 100°C. For 37.5 μm particles, a rather constant Hc/Irs with increasing T is observed for T<70°C, as expected for MD particles; however, a steep rise occurs at approximately 70°C, where the Hc maximum is established. For annealed particles, the total weak-field (160 A m-1~2 Oe) thermoremanent magnetization ITRM versus D plotted on a log-log scale shows a constant value for approximately 1<=D<=6 μm, followed by a straight line in the range approximately 6<=D<=40-50 μm, marking the law ITRM ~ D-p, p~0.53, which appears to be valid for the grain-size region ascribed to PSD particles; for larger particles a smooth transition takes place to a constant value typical for MD particles. Very similar behaviour is established for the analogous curve of the intensity of anhysteretic remanent magnetization, IARM, induced in a field of 160 A m-1. The variation of the ratio IARM/ITRM with grain size D is comparatively weak; it is given by a straight line on a semi-log scale, with values for annealed particles between 0.3 and 0.55 in the whole size range.
Schmidbauer E.
Zitzelsberger A.
No associations
LandOfFree
Temperature dependence of magnetic hysteresis properties, and thermoremanent and anhysteretic remanent magnetization of stress-controlled synthetic 1-125 μm titanomagnetite (Fe2.3Ti0.7O4) particles 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 Temperature dependence of magnetic hysteresis properties, and thermoremanent and anhysteretic remanent magnetization of stress-controlled synthetic 1-125 μm titanomagnetite (Fe2.3Ti0.7O4) particles, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Temperature dependence of magnetic hysteresis properties, and thermoremanent and anhysteretic remanent magnetization of stress-controlled synthetic 1-125 μm titanomagnetite (Fe2.3Ti0.7O4) particles will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1448556