| NUKLEONIKA 2013, 58(1):43-46
STRUCTURAL, MAGNETIC, AND MOSSBAUER EFFECT STUDIES
OF BORNITE
Janusz Przewonik1, Jan Żukrowski1, Łukasz Gondek1, Karolina Gčska1,
Andrzej Lemański1, Czesław Kapusta1, Adam Piestrzyński2
1 AGH University of Science and Technology,
Faculty of Physics and Applied Computer Science, Department of Solid State Physics,
al. A. Mickiewicza 30, 30-059 Krakow, Poland
2 AGH University of Science and Technology,
Faculty of Geology, Geophysics and Environmental Protection,
al. A. Mickiewicza 30, 30-059 Krakow, Poland
The results of a combined study of bornite with Mössbauer spectroscopy, X-ray diffraction and DC magnetometry are reported. The orthorhombic crystallographic structure of the mineral is observed at 15 K and 300 K. It exhibits an increase of the orthorhombic distortion with decreasing temperature. Magnetic susceptibility shows a Curie-Weiss like behaviour between 230 K and 380 K corresponding to the effective magnetic moment of 7.2(3) ”B per formula unit. The material undergoes a transition to an antiferromagnetic-like state at 75 K. Mössbauer spectra at the paramagnetic range are doublets with a small quadrupole splitting and the isomer shift corresponding to a high spin Fe3+ state. Upon magnetic ordering, a coexistence of the paramagnetic doublet with a broadened magnetic sextet is observed indicating an inhomogeneous character of the magnetic transition. The hyperfine field of 350 kOe at 4.2 K is much lower than that observed for a high spin Fe3+ in oxides (510 kOe) which is attributed to covalence effects and a possible copper contribution to the effective magnetic moment of the compound.
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