Home (magnetism)

Fe, Iron

Wikipedia (It is a metal in the first transition series. It by mass is the most common element on Earth, forming much of Earth's outer and inner core)
Electronic configuration: Fe 1s2 2s2 2p6 3s2 3p6 3d6 4s2 with a net moment of 4 BM of 4 unpaired d electrons, Fe2+ is Fe minus 4s2 again with 4 unpaired d electrons, Fe3+ 1s2 2s2 2p6 3s2 3p6 3d56 4s2 with 5 BM.
Magnetism: metal is ferroomagnet at rooom temperature
Link to Iron Oxides
Low spin - intermediate spin - high spin Fe(III) (Figure 2)


alpha Fe2O3

= hematite, the most stable Fe2O3, our measurements (IMFM, Ljubljana, 2014) on bulk sample (Morin transition at 250 K): MH and zfcfc.
With decreasing the particles' size, Morin transition shifts to lower temperatures. (O. Ozdemir, D. J. Dunlop, T. S. Berquo, G3 9, 2008)
Hematite nanoparticles Inset in Fig. 9 is for M(H) bulk hematite.
Synthesis and magnetic properties of concentrated alpha-Fe2O3 nanoparticles in a silica matrix.


Fe3O4

= magnetite, Magnetite is a mineral and one of the main iron ores. With the chemical formula Fe3O4, it is one of the oxides of iron. Magnetite is ferrimagnetic (wiki).
At low temperatures, magnetite undergoes a crystal structure phase transition from a monoclinic structure to a cubic structure known as the Verwey transition. The Verwey transition occurs around 121 K and is dependent on grain size, domain state, and the iron-oxygen stoichiometry. An isotropic point also occurs near the Verwey transition around 130 K, at which point the sign of the magnetocrystalline anisotropy constant changes from positive to negative.[10] The Curie temperature of magnetite is 858 K (585 deg C). (wiki)
zfc and fc, Verwey transition.
Fe3O4 nanoparticles, superspin.


ZrFe2

In 1968, Kai et al. found that ZrFe2 is a typical ferromagnet, with a Curie temperature of 630 K and a magnetization of 88 emu/g. PHYSICAL REVIEW B VOLUME 27, NUMBER 11 1 JUNE 1983, Electronic structure, superconductivity, and magnetism in the C 15 compounds ZrV2, ZrFe2, and ZrCo2, B.M. Klein, W. E. Pickett, D. A. Papaconstantopoulos, and L. L. Boyer