Abstract
We conduct a theoretical study of the temperature dependence of the spin polarization ( ) and the magnetoresistance (MR) ratio using the double exchange (DE) model for ferromagnetic tunnel junctions with half-metallic systems. It is shown that the strong exchange coupling in the DE model plays an important role in the temperature dependence of both and the MR ratio; their values can be less than the maximum values expected for half-metallic systems at low temperatures, and the MR ratio decreases more rapidly than with increasing temperature. The calculated results, however, indicate that the MR ratio may still be large at high temperatures near the Curie temperature.
- Received 27 July 1999
DOI:https://doi.org/10.1103/PhysRevLett.84.2501
©2000 American Physical Society