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Physical Society ColloquiumInterview for Faculty PositionPrecessional magnetic switching dynamicsWayne HiebertIMECSpintronics is a very active area of nanoscience based on the electron spin degree of freedom and offering the potential for novel devices. As a few examples, giant magnetoresistance revolutionized the magnetic recording industry within 10 years of its discovery, MRAM promises to be a fast, non-volatile, low-power, universal memory, and quantum computing remains a flagship goal based on the unique functionality of spin. In the case of developed technologies, devices are rapidly approaching fundamental frequency limits of operation. In all cases (developed and conceptual), speed is of primary importance. Following spin motions (magnetization in the case of a ferromagnet) such as fast magnetic switching becomes paramount for further progress.This presentation will discuss a technique that has allowed key advances in the spatially and temporally resolved observation of magnetization dynamics: time resolved scanning magneto-optic Kerr microscopy. The fundamental forms of magnetic switching have finally been observed experimentally (that is, filmed in progress at an effective rate of 20 billion frames per second). Further, magnetic switching by its ultimate quasiclassical form, gyroscopic precession, has recently been captured and well characterized for the first time, finally completing a pursuit that has had a 45 year history. These results have immediate implications for magnetic recording and MRAM devices. Future work will probe more mid-term questions including spin-momentum-transfer in magnetic layers and spin precession in the semiconductor environment.
Friday, March 21st 2003, 16:00
Ernest Rutherford Physics Building, R.E. Bell Conference Room (room 103) |