Powder Diffraction Refinements of the Structure of Magnetite (Fe_3O_4) Below the Verwey Transition

摘要

Magnetic is a classic example of a mixed-valent transition metal oxide,in which electronic conductivity and ferromagnetism result from electron hopping between octahedrally coordinated Fe~(2+) and Fe~(3+) states.Below the 122 K Verwey transition,the conductivity falls by a factor of approx 100 and a complex monoclinic (or triclinic) superstructure of the high temperature cubic spinelarrangement is adopted.