Magnetic Tunneling Effect in Ferromagnet/Al2O3/Ferromagnet Junctions.

Abstract
The magnetic tunneling effect was investigated for 80 NiFe/Al2O3/Co, Fe/Al2O3/Co, 50FeCo/Al2O3/Co, and Fe/ Al2O3/Fe junctions in the temperature range from 4.2 K to 300 K. Ferromagnetic layers were prepared by an electron beam evaporation method, and Al2O3 layers were formed by oxidizing Al films prepared by the RF sputtering method. The magnetoresistance ratios of these junctions at 4.2 K were 4.3%, 8.5%, 8.3%, and 30%, respectively. The temperature dependence of the tunneling conductance is discussed in terms of Stratton's theory.