Evidence for magnetostrictive control of intrinsic susceptibility and coercive force of multidomain magnetite in rocks

Hodych, J. P.

doi:10.1016/0031-9201(86)90091-9

Cited by 38 publications

(36 citation statements)

References 12 publications

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“…Similar to reports by Belov (1993) and Hodych (1986), Muxworthy also show a small peak at the Verwey transition for the 3.0 fim particles of Fe304, but not for the larger particles. This peak rises to~7% above the magnetic susceptibility on the high-temperature side He (see Sugiura, 1977;Wasilewski, 1981;Brecher and Arrhenius, 1974).…”

Section: Verwey Transitionsupporting

confidence: 73%

Magnetic study of magnetite in the Tagish Lake meteorite

Thorpe¹,

Senftle²,

Grant³

2002

Meteorit & Planetary Scien

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Abstract-The saturation magnetization, saturation remanent magnetization, the coercive, and remanent coercive force were determined at room and liquid nitrogen temperatures for three pieces of the Tagish Lake meteorite. The results are compared to similar data for four other chondrites (Allende, Murray, Orgueil, and Murchison). The data suggests that the Tagish Lake meteorite is magnetically homogeneous, and is not as magnetically hard as the comparison chondrites. The magnetization measurements indicate that it contains about 10-11 % multi-domain magnetite. Magnetic susceptibility measurements on all the samples from 77 K to room temperature showed a Verwey transition for all the samples which contain a significant amount of multi-domain magnetite. The coercive force data further indicate that the magnetite in Tagish Lake is multi-domain and that the grain size is small and approximately 4-9.um.

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Section: Verwey Transitionsupporting

confidence: 73%

Magnetic study of magnetite in the Tagish Lake meteorite

Thorpe¹,

Senftle²,

Grant³

2002

Meteorit & Planetary Scien

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“…H c decreases with cooling from 300 K to a minimum of 0.035 mT around T i = 130 K. Recent work on natural single crystals of magnetite has shown that H c varies with temperature as V s /M s between 300 and 170 K, indicating the importance of magnetoelastic anisotropy over this temperature range [7]. Coarse-grained magnetites behave similarly [35]. Below 170 K, the coercivity is controlled by magnetocrystalline anisotropy as well [7], and this accounts for the marked minimum at 130 K. In crossing the Verwey transition, H c increases very sharply by almost a factor 40.…”

Section: Low-temperature Coercive Forcementioning

confidence: 76%

Changes in remanence, coercivity and domain state at low temperature in magnetite

Özdemir

Dunlop

Moskowitz

2002

Earth and Planetary Science Letters

161

116

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Submicron magnetite crystals with mean sizes of 0.037, 0.10 and 0.22 Wm undergo major changes in hysteresis properties and domain states in crossing the Verwey transition (T V W120 K). The 0.037 Wm crystals are single-domain (SD) both in the cubic phase at room temperature T 0 and in the monoclinic phase below T V . The 0.10 and 0.22 Wm crystals have a mixture of SD and two-domain (2D) states at room temperature T 0 , but mainly SD structures below T V , in agreement with micromagnetic calculations. Coercive force H c increases on cooling through T V , by a factor 3^5 in the submicron magnetites and 40 in a 1.3 mm single crystal, because of the high crystalline anisotropy and magnetostriction of monoclinic magnetite. As a result, domain walls and SD moments are so effectively pinned below T V that all remanence variations in warming or cooling are reversible. However, between W100 K and T 0 , remanence behavior is variable. Saturation remanence (SIRM) produced in monoclinic magnetite at 5 K drops by 70^100% in warming across T V , with minor recovery in cooling back through T V (ultimate levels at 5 K of 23^37% for the submicron crystals and 3% for the 1.3 mm crystal). In contrast, SIRM produced in the cubic phase at 300 K decreases 5^35% (submicron) or s 95% (1.3 mm) during cooling from 300 to 120 K due to continuous re-equilibration of domain walls, but there is little further change in cooling through T V itself. However, the submicron magnetites lose a further 51 5% of their remanence when reheated through T V . These irreversible changes in cycling across T V , and the amounts of the changes, have potential value in determining submicron magnetite grain sizes. The irreversibility is mainly caused by 2DCSD transformations on cooling through T V , which preserve or enhance remanence, while SDC2D transformations on warming through T V cause remanence to demagnetize. ß

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“…There are reports in literature of peaks in χ at T k , [8,19], however the only sample to display a peak near T v was the small H(3.0 µm) sample [ Figure 1b]. It is suggested that the peak could be an indicator of grain size.…”

Section: Discussion Frequency Dependency Of Susceptibility At Low-temmentioning

confidence: 99%

Low-temperature susceptibility and hysteresis of magnetite

Muxworthy

1999

Earth and Planetary Science Letters

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Evidence for magnetostrictive control of intrinsic susceptibility and coercive force of multidomain magnetite in rocks

Cited by 38 publications

References 12 publications

Magnetic study of magnetite in the Tagish Lake meteorite

Magnetic study of magnetite in the Tagish Lake meteorite

Changes in remanence, coercivity and domain state at low temperature in magnetite

Low-temperature susceptibility and hysteresis of magnetite

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