_____________________________________________________________________
Fe3O4
Spinel structure (magnetite)
X
a calculations: Phys. Rev. B17, 484 (1978)
Phase transition:
T=850K
® ferromagnetic orderT=122K
® Verwey transition with charge ordering of Fe2+, Fe3+. Several models. See eg. Phys. Rev. B14, 200 (1976)
r
= 4.81 g/cm3 (variable) cited in Physical Acoustics VIB 419
Sound velocities: 4.07-4.34 (l), and 2.09-2.25 (t) *105 cm/sec.
Ref.: Geophys. 28, 658 (1963)
Pressure dependencies of l-waves 431
_____________________________________________________________________