Electrical spin injection and accumulation at room temperature in an all-metal mesoscopic spin valve

• Published in: Nature (London) Vol. 410; no. 6826; pp. 345 - 348
• Main Authors: Jedema, F. J, Filip, A. T, van Wees, B. J
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 15.03.2001; Nature Publishing Group
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronics; Exact sciences and technology; Giant magnetoresistance; Magnetic properties and materials; Magnetotransport phenomena, materials for magnetotransport; Metals; Physics; Temperature; Nickel base alloys; Geometrical shape; Spin flip; Spin valve; Magnetization; Ferromagnetic materials; Spacing; Iron alloys; Giant magnetoresistance; Solid-solid interfaces; Experimental study; Spin injection; Sandwich structures; Electrodes; Permalloy; Copper; Mesoscopic systems
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/35066533

Finding a means to generate, control and use spin-polarized currents represents an important challenge for spin-based electronics, or 'spintronics'. Spin currents and the associated phenomenon of spin accumulation can be realized by driving a current from a ferromagnetic electrode into a non-magnetic metal or semiconductor. This was first demonstrated over 15 years ago in a spin injection experiment on a single crystal aluminium bar at temperatures below 77 K. Recent experiments have demonstrated successful optical detection of spin injection in semiconductors, using either optical injection by circularly polarized light or electrical injection from a magnetic semiconductor. However, it has not been possible to achieve fully electrical spin injection and detection at room temperature. Here we report room-temperature electrical injection and detection of spin currents and observe spin accumulation in an all-metal lateral mesoscopic spin valve, where ferromagnetic electrodes are used to drive a spin-polarized current into crossed copper strips. We anticipate that larger signals should be obtainable by optimizing the choice of materials and device geometry.