Podrobnosti záznamu

Název
    Low-field variation of magnetic susceptibility and its effect on the anisotropy of magnetic susceptibility of rocks
Údaj o odpovědnosti
    František Hrouda
Autor
    Hrouda, František
Jazyk
    anglicky
Zdrojový dokument - seriál
    Geophysical journal international
Svazek/č.
    Vol. 150
Strany
    p. 715-723
Rok
    2002
Poznámky
    10 obr., 6 tab., 24 bibl.
    il.
    Zkr. název ser.: Geophys. J. int.
Předmětová skupina
    anizotropie
    hematit
    magnetická susceptibilita
    magnetit
    magnetometr
    metoda monokrystalová
    minerály magnetické
    pyrrhotin
Geografické jméno
    Brazílie-Minas Gerais
    Itálie střední
Klíčové slovo
    Anisotropy
    Effect
    Low-field
    Magnetic
    Rocks
    Susceptibility
    Variation
Abstrakt (anglicky)
   The theory of the low-field anisotropy of magnetic susceptibility (AMS) assumes a linear relationship between magnetization and the magnetizing field. This assumption is precisely valid in diamagnetic and paramagnetic minerals by definition, while in ferrimagnetic and antiferromagnetic minerals this relationship is in general non-linear (represented by a hysteresis loop), being linear only with very weak fields in which the initial susceptibility is measured. Recently, it has been shown that, in using common measuring fields, the field-independent susceptibility is measured in magnetite, while in pyrrhotite, haematite and titanomagnetite it may often be outside the initial susceptibility range. The problem can be solved in three ways. The simplest way is using very weak measuring fields (less than 10 A m-1), but this can result in significant lowering of sensitivity and precision.
   The second way is to respect the non-linearity and measure the susceptibility in so many directions that contour diagram of directional susceptibilities can be presented instead of a susceptibility ellipsoid. The third way is to measure the AMS within the Rayleigh law range and calculate the initial directional susceptibilities from which the AMS can be correctly determined using linear theory
Přispěvatel
    Česká geologická služba
Kód přispěvatele
    ČGS (UNM)
Zdrojový formát
    U
Datum vložení
    11. 10. 2007
Datum importu
    8. 8. 2012