Suppression of spin diffusion near a micron-size ferromagnet.
We have used the large gradients generated near the ferromagnetic tip of a magnetic resonance force microscope to locally suppress spin diffusion in a silica sample containing paramagnetic electron spins. By controlling the slice location with respect to the tip, the magnetic field gradient was varied from 0.01 to 36 mT/microm, resulting in a fourfold decrease in T-11 and a similar decrease in T(-1)(1 rho). The observed dependence of the relaxation rates on field gradient is consistent with the quenching of flip-flop interactions that mediate the transport of magnetization between slow and fast relaxing spins.
Budakian
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IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, California 95120-6099, USA.
Mamin
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HJ
Rugar
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