One of the most revolutionary discoveries relating to nanomagnets has to do with"spin polarization". At the endpoint of a long explanation, we learn about how a "tremendous amount of torque" can be induced in a ferromagnet by sub-atomic particles. What use is this?

Nobody knows yet, but one of the natural results would be a microscopic microwave oscillator.

Remember, Reiman's non-Euclidean geometry had no application until Einstein found it essential to the development of his theory of relativity. OK, so it got us in trouble eventually. Hopefully, nanomagnetics will be a kinder technology. I've nabbed a few quotations to explain this new discovery.

The article quoted above is from Nature, September 25, 2003, and here's some more:

The recent discovery that a spin-polarized electrical current can apply a large torque to a ferromagnet, through direct transfer of spin angular momentum, offers the possibility of manipulating magnetic-device elements without applying cumbersome magnetic fields. However, a central question remains unresolved: what type of magnetic motions can be generated by this torque? Theory predicts that spin transfer may be able to drive a nanomagnet into types of oscillatory magnetic modes not attainable with magnetic fields alone, but existing measurement techniques have provided only indirect evidence for dynamical states. The nature of the possible motions has not been determined. Here we demonstrate a technique that allows direct electrical measurements of microwave-frequency dynamics in individual nanomagnets, propelled by a d.c. spin-polarized current. We show that spin transfer can produce several different types of magnetic excitation. Although there is no mechanical motion, a simple magnetic-multilayer structure acts like a nanoscale motor; it converts energy from a d.c. electrical current into high-frequency magnetic rotations that might be applied in new devices including microwave sources and resonators.

Nature
09-25-03

So you may ask, what is "spin polarized electrical current". This is a difficult one for a simple explanation, I'm still trying to get my head around this one. Until tomorrow, here are a few references I've been reading:

"..closely related to the non-commutation of ordinary spatial rotations of a classical particle, in the sense that they're both related to the cross-product of orthogonal vectors."

from:
http://www.mathpages.com/rr/s9-04/9-04.htm

"spin Polarized electrons"

http://nvl.nist.gov/pub/nistpubs/sp958-lide/203-208.pdf

until later,

Dr. Nano