Temperature dependence of magnetic hysteresis

Yu, Yongjae; Tauxe, Lisa; Moskowitz, Bruce M.

doi:10.1029/2003gc000685

Cited by 20 publications

(14 citation statements)

References 68 publications

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“…In Figure 6, GSD estimation is generally well matched with a lognormal volume distribution, but there exists slight deviation at smaller volumes. It is possible that magnetocrystalline contribution [e.g., Yu et al , 2004] may cause such a tiny discrepancy.…”

Section: Discussionmentioning

confidence: 99%

Quantifying grain size distribution of pedogenic magnetic particles in Chinese loess and its significance for pedogenesis

et al. 2005

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[1] Quaternary glacial/interglacial cycles have been imprinted on the Chinese loess/ paleosol sequences through pedogenesis. In order to accurately decode the paleoclimatic signals carried by these pedogenic particles it is essential to quantify the pedogenically produced magnetic particles in terms of mineralogy as well as grain size distribution (GSD). To date, the GSD has not been accurately determined because of the dearth of available means for analyzing extremely fine grained (nanometer-scale) pedogenic magnetic particles. Using low-temperature techniques, we systematically investigated the temperature dependency of c fd (defined as c 1Hz À c 10Hz , where c 1Hz and c 10Hz are AC magnetic susceptibility measured at 1 and 10 Hz, respectively) from two characteristic loess profiles, one located at the western Chinese Loess Plateau and the other in the central plateau. On the basis of Néel theory for a shape anisotropy dominant grain and experimental analysis at low temperatures, a quantitative GSD for pedogenic particles in Chinese loess/paleosols was constructed. We found that the dominant magnetic grain size lies just above the superparamagnetic/single-domain threshold ($20-25 nm) and that the GSD is almost independent of the degree of pedogenesis. This observation agrees well with other constraints from previous studies. This new GSD model improves our understanding of the pedogenic processes in Chinese loess, enabling further explicit linkage of environmental magnetism to paleoclimate changes.

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Section: Discussionmentioning

confidence: 99%

Quantifying grain size distribution of pedogenic magnetic particles in Chinese loess and its significance for pedogenesis

et al. 2005

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“…Values of remanence coercivity ( B cr ) were obtained from back‐field measurements. The squareness (=ratio of M rs / M s ) versus coercivity plot of the 60 chips from An‐ei, Iwoyama, Nabeyama, Ohachi, and Ojodake formed a linear correlation with a mean slope of ≈0.01 mT −1 (Figure 4a), indicative for the presence of low‐Ti titanomagnetite [ Yu et al , 2004b]. The ratio of M rs / M s and B cr / B c for the 60 chips lie in the pseudo‐single‐domain (PSD) range according to the conventional criteria [ Day et al , 1977] or PSD trend curves [ Dunlop , 2002] (Figure 4b).…”

Section: Rock Magnetic Analysismentioning

confidence: 99%

“…Hysteresis properties displayed in (a) a remanence ratio versus coercivity diagram [ Yu et al , 2004b] and (b) a Day plot [ Day et al , 1977]. In a Day plot, results fall in the PSD range or match well with the single‐domain and multidomain mixing trend curves [ Dunlop , 2002].…”

Section: Rock Magnetic Analysismentioning

confidence: 99%

High‐fidelity paleointensity determination from historic volcanoes in Japan

2012

J. Geophys. Res.

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Providing high‐fidelity paleointensity estimates is pivotal to identify temporal fluctuation of ancient geomagnetic field. Despite abundance of available paleointensity data in Japan, only dozen of them satisfy modern standards with systematic alteration checks. High‐fidelity paleointensity estimates were obtained from historic andesitic lavas collected from Mt. Aso (Ojodake, ≈700 BC), Mt. Kirishima (Iwoyama, AD 1768; Ohachi, AD 1235), and Mt. Sakurajima (An‐ei, AD 1779; Nabeyama, AD 764–766). Variation of geomagnetic field intensity is distinctively different from the prediction of global models (ARCH3k.1, CALS3k.3, CALS3k.4, CALS7k.2, and CALS10k.1b) for the past 4000 years in Japan. The compilation of high‐fidelity Thellier data set in Japan showed two obvious high intensities at AD 590–765 and AD 1330–1435 and one low intensity at ≈700 BC. These time intervals with anomalous high/low intensities are nearly identical to three of the four potential archeomagnetic jerks recognized from the European archeomagnetic data, implying that the archeomagnetic jerks were global (or at least northern hemispheric) features. To improve the poor representation of regional geomagnetic field variation with respect to the global model prediction, more high‐fidelity paleointensity determinations are required in East Asia.

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“…Recent methodological advances in paleointensity techniques have substantially increased the success rates in obtaining reliable paleointensities from lavas since Thellier and Thellier [] proposed their paleointensity method in 1959 [e.g., Coe , ; Aitken et al ., ; Hill and Shaw , ; Riisager and Riisager , ; Krasa et al ., ; Tauxe and Staudigel , ; Yu et al ., ; Yu and Tauxe , ; Dekkers and Böhnel , ; Fabian and Leonhardt , ; Muxworthy , ]. The chance of obtaining a reliable paleointensity estimate for a given cooling unit can be increased from the typical 10–20% up to 60–70% by sampling cooling units at multiple locations, applying different paleointensity methods to sister specimens, and subjecting the paleointensity results to rigorous quality criteria [ de Groot et al ., ].…”

Section: Introductionmentioning

confidence: 98%

Magnetic properties and paleointensities as function of depth in a Hawaiian lava flow

Groot

Dekkers

Visscher

et al. 2014

Geochem. Geophys. Geosyst.

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The outcome of paleointensity experiments largely depends on the rock-magnetic properties of the samples. To assess the relation between volcanic emplacement processes and rock-magnetic properties, we sampled a vertical transect in a 6 m thick inflated lava flow at Hawaii, emplaced in 588 AD. Its rock-magnetic properties vary as function of distance from the flow top; the observations can be correlated to the typical cooling rate profile for such a flow. The top and to a lesser extent the bottom parts of the flow cooled faster and reveal a composition of TM60 in which the magnetic remanence is carried by finegrained titanomagnetites, relatively rich in titanium, with associated low Curie and unblocking temperatures. The titanomagnetite in the slower cooled central part of the flow is unmixed into the magnetite and € ulvospinel end-members as evidenced by scanning electron microscope observation. The remanence is carried by coarse-grained magnetite lamella ( TM0) with high Curie and unblocking temperatures. The calibrated pseudo-Thellier results that can be accepted yield an average paleointensity of 44.1 6 2.4 lT. This is in good agreement with the paleointensity results obtained using the thermal IZZI-Thellier technique (41.6 6 7.4 lT) and a recently proposed record for Hawaii. We therefore suggest that the chance of obtaining a reliable paleointensity from a particular cooling unit can be increased by sampling lavas at multiple levels at different distances from the top of the flow combined with careful preliminary testing of the rockmagnetic properties.

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Temperature dependence of magnetic hysteresis

Cited by 20 publications

References 68 publications

Quantifying grain size distribution of pedogenic magnetic particles in Chinese loess and its significance for pedogenesis

Quantifying grain size distribution of pedogenic magnetic particles in Chinese loess and its significance for pedogenesis

High‐fidelity paleointensity determination from historic volcanoes in Japan

Magnetic properties and paleointensities as function of depth in a Hawaiian lava flow

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