(1) Laboratoire de Physique des Matériaux, UMR CNRS 7556, B.P. 239, 54506 Vanduvre-les-Nancy Cedex, France;(2) CEMES-CNRS-Groupe NanoMatériaux, 29 rue Jeanne Marvig, B.P. 94347, 31055 Toulouse Cedex, France
Abstract:
Magnetic tunnel junctions with a barrier of magnesium oxide were prepared by plasma oxidation of sputter-deposited magnesium. They show magnetoresistance ratios up to 4.5% at room temperature and 5.5% at low temperatures for barrier thickness of 1.6 nm. The material exhibits low barrier heights of around 0.7 eV. These junctions follows the predictions of the free electron model which contrast with the predictions of band structure calculations and experimental results on epitaxial MgO based tunnel junctions.Received: 23 April 2004, Published online: 3 August 2004PACS:
73.40.Rw Metal-insulator-metal structures - 75.70.Pa Giant magnetoresistance - 73.40.Gk Tunneling - 73.61.Ng Insulators