ISBN-13: 9783639105926 / Angielski / Miękka / 2009 / 124 str.
ISBN-13: 9783639105926 / Angielski / Miękka / 2009 / 124 str.
In recent years, materials and devices that are based on the manipulation of the electron''s spin are often termed spintronic. Spintronic devices have already had enormous technological impact as highly sensitive field sensors used in all magnetic data storage devices today. Among recent advances in spintronics, magnetic tunnel junctions have been under intensive study and are poised to become one of the most widely used spintronic devices. Using sputter deposited crystalline tunnel barriers formed from magnesium oxide (MgO) we show remarkably high polarization values, as high as 90%. We show alternative superconducting materials, NbN can be used as a spin detector. We observed that by deliberately introducing small magnetic nanoparticles in the interior of MgO tunnel barriers, there is evidence for Kondo-assisted tunneling in planar magnetic tunnel junctions. Introduction into the tunnel barrier of thin insulating antiferromagnetic oxide layers, we show that such layers can lead to highly asymmetric voltage dependences of tunneling magnetoresistance, and negative values of tunneling magnetoresistance.