HR: 0830h
AN: GP31B-0756    [PDF]
TI: On Curie (Neel) Temperature Determination Using Magnetic Susceptibility
AU: * Petrovsky, E
EM: edp@ig.cas.cz
AF: Geophysical Institute ASCR, Bocni II/1401, Prague 4, 14131 Czech Republic
AU: Kapicka, A
EM: kapicka@ig.cas.cz
AF: Geophysical Institute ASCR, Bocni II/1401, Prague 4, 14131 Czech Republic
AB: Until recently, temperature dependence of induced magnetization was used practically exclusively in order to determine Curie (Neel) temperature of minerals. In theory, Curie temperature (Tc) is defined as temperature at which spontaneous alignment of atomic magnetic moments vanishes. In practice, several approximations have been used, mostly based on linear fit(s) to section(s) of magnetization decay. This method is strongly limited by sensitivity of the instrument used, because at temperatures close to Tc magnetization values are very low. Recently, newly developed instruments enabled also the use of temperature dependence of magnetic susceptibility. However, despite completely different physical basis, in many cases the same methods for determining Tc have been used as in the previous instance. In our contribution we show that this approach may result in significant error, even more than 100degC. We will demonstrate the importance of Curie-Weiss paramagnetic law and the use of paramagnetic Curie temperature when using temperature dependence of magnetic susceptibility for the Curie (Neel) temperature determination.
DE: 1540 Rock and mineral magnetism
DE: 1594 Instruments and techniques
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2003 Fall Meeting