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  • 1
    Publication Date: 2021-07-03
    Description: Stable paleomagnetic information in meteoritic metal is carried by the “cloudy zone”: ~1–10 μm‐wide regions containing islands of ferromagnetic tetrataenite embedded in a paramagnetic antitaenite matrix. Due to their small size and high coercivity (theoretically up to ~2.2 T), the tetrataenite islands carry very stable magnetic remanence. However, these characteristics also make it difficult to image their magnetic state with the necessary spatial resolution and applied magnetic field. Here, we describe the first application of X‐ray holography to image the magnetic structure of the cloudy zone of the Tazewell IIICD meteorite with spatial resolution down to ~40 nm and in applied magnetic fields up to ±1.1 T, sufficient to extract high‐field hysteresis data from individual islands. Images were acquired as a function of magnetic field applied both parallel and perpendicular to the surface of a ~100 nm‐thick slice of the cloudy zone. Broad distributions of coercivity are observed, including values that likely exceed the maximum applied field. Horizontal offsets in the hysteresis loops indicate an interaction field distribution with half width of ~100 mT between the islands in their room temperature single‐domain state, providing a good match to first‐order reversal curve diagrams. The results suggest that future models of remanence acquisition in the cloudy zone should take account of strong interactions in order to extract quantitative estimates of the paleofield.
    Description: Plain Language Summary: Magnetic fields played a significant role in the formation of the solar system and the evolution of the early planetary bodies in the first few million years after solar system formation. Knowledge about magnetic fields in the early solar system can be obtained from meteorites. Some meteorite types contain abundant iron‐nickel alloy that contains nanoscale “cloudy zone” regions (named after their appearance in an optical microscope) that can preserve magnetic information over 4.5 billion years. The cloudy zone is a complex material consisting of magnetically stable nanoscale particles embedded in a nonmagnetic matrix in very close proximity to one another. The fine scale and extreme magnetic stability of the cloudy zone make it challenging to study using conventional magnetic microscopy techniques. Here, we apply X‐ray holography for the first time to image the magnetization of individual magnetic particles and how they respond to magnetic fields. This new approach enables us to measure the magnetic properties of individual nanoscale particles, providing the first direct measurement of their magnetic stability and the strength of particle interactions. These measurements will improve our understanding of the magnetic information carried by the cloudy zone, and of how to extract information about solar system magnetic fields.
    Description: Key Points: X‐ray holography enables magnetization of natural samples to be imaged with ~40 nm resolution and in applied magnetic fields up to ±1.1 T. Meteoritic cloudy zone consists of strongly interacting single‐domain particles with single‐particle coercivities up to 1 T. Average interaction fields between particles in the cloudy zone are of the order 100–200 mT.
    Description: European Commission (EC) http://dx.doi.org/10.13039/501100000780
    Description: Europen Commission
    Description: European Research Council (ERC) http://dx.doi.org/10.13039/501100000781
    Description: European Research Council under the European Union's Seventh Framework Programme
    Keywords: 523 ; 538.7 ; X‐ray holography ; cloudy zone ; Tazewell meteorite
    Type: article
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 106 (1984), S. 6952-6955 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 114 (2001), S. 48-53 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A parallel implementation of the spin-free one-electron Douglas–Kroll–Hess (DKH) Hamiltonian in NWChem is discussed. An efficient and accurate method to calculate DKH gradients is introduced. It is shown that the use of a standard (nonrelativistic) contracted basis set can produce erroneous results for elements beyond the first row elements. The generation of DKH contracted cc-pVXZ(X=D,T,Q,5) basis sets for H, He, B–Ne, Al–Ar, and Ga–Br is discussed. The effect of DKH at the Hartree–Fock level on the bond distances, vibrational frequencies, and total dissociation energies for CF4, SiH4, SiF4, and Br2CO is discussed. It is suggested that the predominant effect of the scalar relativistic correction on the total dissociation energy can be calculated at the Hartree–Fock level if an adequate basis set is used. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 17 (1964), S. 325-331 
    ISSN: 0001-5520
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 177 (1956), S. 977-979 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] REPRODUCTION in the European badger has been the subject of controversy for many years, and one authority or another has made claims for each month of the year to be that. of the mating season. Those investigators1-3 who have recently examined the reproductive pattern comment at length on the ...
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 173 (1954), S. 86-87 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] It had been desired to investigate the effects of raised external pressure on the animal's circulation, in an attempt to simulate the conditions during diving. Two live pups were satisfactorily and easily anaesthetized by Finer's method2. Attempts were made to place the anaesthetized animal on its ...
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 167 (1951), S. 443-444 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The keeper at Woburn Park informs us that mating occurs in July; but the stags begin the 'rounding up' of the hinds in June. Mating usually occurs at night. Parturition has been reported in early April, but the usual date is mid-April to May; the latest date recorded was in September, the latter ...
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 168 (1951), S. 771-772 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] THERE is convincing physiological evidence indicating that, in several species of mammals, including man, horse and donkey, oestrogens and progesterone are elaborated by extra-ovarian tissues1'2. It is generally believed that the placenta represents the new source, though the available evidence ...
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 188 (1960), S. 1068-1070 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] ALL mammals can withstand complete submersion,in water for a little while ; but some forms are able to remain submerged at considerable depths for remarkable periods of time. It will be obvious that there are few accurate observations on the maximum length of time for which any mammal can remain ...
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 381 (1996), S. 407-409 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] It has been recognized for some time that non-equilibrium cation ordering in minerals might provide a means to measure rock cooling rates, from early work on Mg/Fe ordering in amphi-boles6 and extensive studies of pyroxenes7'8 to more recent analysis of Al/Si ordering in alkali feldspars9. ...
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