Analysis of Strong-Field Hysteresis in High Coercivity Magnetic Minerals

Kosterov, Andrei; Sergienko, E. S.; Iosifidi, A. G.; Харитонский, П. В.; Yanson, Svetlana

doi:10.1007/978-3-030-21788-4_10

Cited by 3 publications

(2 citation statements)

References 20 publications

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“…It is important to note that the presence of hematite, confirmed by CRS, is not directly visible by the magnetic hysteresis loops owing to its low saturation magnetization of 0.3 Am 2 kg -1 (Morrish, 1995;Cornell and Schwertmann, 2003), one order of magnitude smaller than that of magnetite (92-100 Am 2 kg -1 ) (Dunlop and Ozdemir, 1997;Cornell and Schwertmann, 2003). Raman shift (cm -1 ) Going into the intermediate region between 1 and 3 cm, the magnetic hysteresis loops become wasp-waisted (Figure 2e), as observed in archaeological samples containing ε-Fe2O3 (McIntosh et al, 2007(McIntosh et al, , 2011Lopez-Sanchez et al, 2017a;Molina-Cardin et al, 2018;Calvo-Rathert et al, 2019;Kostadinova-Avramova et al, 2019a;Lee et al, 2019;Kosterov et al, 2020). The wasp-waisted hysteresis shape is due to two distinct magnetic populations with highly contrasting coercivities (Figure 2e): (1) a low coercivity, high remanence contribution, and (2) a high coercivity, low remanence contribution (Tauxe et al, 1996).…”

Section: Magnetic Hysteresis Loops and Raman Characterization Along A...mentioning

confidence: 80%

Further progress in the study of epsilon iron oxide in archaeological baked clays

López-Sánchez

Palencia-Ortas

Campo

et al. 2020

Physics of the Earth and Planetary Interiors

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Section: Magnetic Hysteresis Loops and Raman Characterization Along A...mentioning

confidence: 80%

Further progress in the study of epsilon iron oxide in archaeological baked clays

López-Sánchez

Palencia-Ortas

Campo

et al. 2020

Physics of the Earth and Planetary Interiors

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“…Meanwhile, the inflection point can alternatively be explained by the presence of ε-Fe 2 O 3 . The magnetic property of ε-Fe 2 O 3 corresponds to a high coercive field and low unblocking temperature (e.g., Tuček et al 2010;López-Sánchez et al 2017;Kosterov et al 2020b). Furthermore, the occurrence of ε-Fe 2 O 3 is related to the anthropogenic fire (e.g., López-Sánchez et al 2017;Kosterov et al 2020a) or the vegetation change (McClean et al 2001).…”

Section: Magnetic Minerals In the Speleothemmentioning

confidence: 99%

High spatial resolution magnetic mapping using ultra-high sensitivity scanning SQUID microscopy on a speleothem from the Kingdom of Tonga, southern Pacific

Fukuyo

Oda

Yokoyama

et al. 2021

Earth Planets Space

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Speleothems are ideal archives of environmental magnetism and paleomagnetism, since they retain continuous magnetic signals in stable conditions and can be used for reliable radiometric dating using U-series and radiocarbon methods. However, their weak magnetic signals hinder the widespread use of this archive in the field of geoscience. While previous studies successfully reconstructed paleomagnetic signatures and paleoenvironmental changes, the time resolutions presented were insufficient. Recently emerging scanning SQUID microscopy (SSM) in this field can image very weak magnetic fields while maintaining high spatial resolution that could likely overcome this obstacle. In this study, we employed SSM for high spatial resolution magnetic mapping on a stalagmite collected at Anahulu cave in Tongatapu Island, the Kingdom of Tonga. The average measured magnetic field after 5 mT alternating field demagnetization is ca. 0.27 nT with a sensor-to-sample distance of ~ 200 µm. A stronger magnetic field (average: ca. 0.62 nT) was observed above the grayish surface layer compared to that of the white inner part (average: ca. 0.09 nT) associated with the laminated structures of the speleothem at the submillimeter scale, which scanning resolution of the SSM in this study is comparable to the annual growth rates of the speleothem. The magnetization of the speleothem sample calculated from an inversion of isothermal remanent magnetization (IRM) also suggests that the magnetic mineral content in the surface layer is higher than the inner part. This feature was further investigated by low-temperature magnetometry. Our results show that the main magnetic carriers of the speleothem under study are magnetite and maghemite and it can contain hematite or ε-Fe2O3. The first-order reversal curve (FORC) measurements and the decomposition of IRM curves show that this speleothem contains a mixture of magnetic minerals with different coercivities and domain states. The contribution from maghemite to the total magnetization of the grayish surface layer was much higher than the white inner part. Such differences in magnetic mineralogy of the grayish surface layer from that of the inner part suggest that the depositional environment shifted and was likely changed due to the oxidative environment.

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High-coercivity magnetic minerals in archaeological baked clay and bricks

Kosterov

Kovacheva

Kostadinova‐Avramova

et al. 2020

Geophysical Journal International

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Summary The thorough understanding of magnetic mineralogy is a prerequisite of any successful palaeomagnetic or archaeomagnetic study. Magnetic minerals in archaeological ceramics and baked clay may be inherited from the parent material, or, more frequently, formed during the firing process. The resulting magnetic mineralogy may be complex, including ferrimagnetic phases not commonly encountered in rocks. Towards this end, we carried out a detailed rock magnetic study on a representative collection of archaeological ceramics (baked clay from combustion structures and bricks) from Bulgaria and Russia. Experiments included measurement of isothermal remanence acquisition and demagnetization as a function of temperature between 20° C and > 600° C. For selected samples, low-temperature measurements of saturation remanence and initial magnetic susceptibility between 1.8 K and 300 K have been carried out. All studied samples contain a magnetically soft mineral identified as maghemite probably substituted by Ti, Mn and/or Al. Stoichiometric magnetite has never been observed, as evidenced by the absence of the Verwey phase transition. In addition, one or two magnetically hard mineral phases have been detected, differing sharply in their respective unblocking temperatures. One of these unblocking between 540° C and 620° C is believed to be substituted hematite. Another phase unblocks at much lower temperatures, between 140° C and 240° C, and its magnetic properties correspond to an enigmatic High Coercivity, Stable, Low-unblocking Temperature (HCSLT) phase reported earlier. In a few samples high- and low unblocking temperature, magnetically hard phases appear to coexist, in the others the HCSLT phase is the only magnetically hard mineral present.

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Analysis of Strong-Field Hysteresis in High Coercivity Magnetic Minerals

Cited by 3 publications

References 20 publications

Further progress in the study of epsilon iron oxide in archaeological baked clays

Further progress in the study of epsilon iron oxide in archaeological baked clays

High spatial resolution magnetic mapping using ultra-high sensitivity scanning SQUID microscopy on a speleothem from the Kingdom of Tonga, southern Pacific

High-coercivity magnetic minerals in archaeological baked clay and bricks

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