Abstract
A study has been made of the internal fields acting on nuclei in some spinel ferrites, with particular reference to the low-temperature order-disorder transition in magnetite, using the techniques of Mössbauer absorption. For the ions at both the octahedral and tetrahedral sites in nickel ferrite (Ni) at 300°K, at 85° and 300°K, and magnetite () at 85°K, the effective magnetic field at the nuclei is the same and equal to about 5.1× oe. In magnetite, the value of in the ions is about 4.5× oe at 85°K. Measurements on at room temperatures provide a microscopic confirmation of Verwey's hypothesis that above the transition temperature of magnetite there is a fast exchange between the ferrous and ferric ions in the octahedral sites.
- Received 27 January 1961
DOI:https://doi.org/10.1103/PhysRev.122.1447
©1961 American Physical Society