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Direct-Current Induced Dynamics in Co90Fe10/Ni80Fe20 Point Contacts



William Rippard, Matthew Pufall, Shehzaad F. Kaka, Stephen E. Russek, Thomas J. Silva


We have directly measured coherent high-frequency magnetization dynamics in ferromagnetic films induced by a spin-polarized dc current. The precision frequency can be tuned over a range of several gigahertz by varying the applied current. The frequencies of excitation also vary with applied field, resulting in a microwave oscillator that can be tuned from below 5 to above 40 GHz. This novel method of inducing high-frequency dynamics yields oscillation having quality factors from 200 to 800. We compare our results with those from single-domain simulation of current induced dynamics.
Physical Review Letters


magnetization dynamics, point contacts, rf excitations, spin transfer


Rippard, W. , Pufall, M. , Kaka, S. , Russek, S. and Silva, T. (2004), Direct-Current Induced Dynamics in Co<sub>90</sub>Fe<sub>10</sub>/Ni<sub>80</sub>Fe<sub>20</sub> Point Contacts, Physical Review Letters, [online], (Accessed June 24, 2024)


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Created January 15, 2004, Updated October 12, 2021