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[ Last edited by ÄûÃÊÊ÷ on 2013-3-14 at 16:24 ]
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2Â¥2013-03-14 16:25:29
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And the conductance is quantized in units 2e2/h for non-magnetic materials and in units e2/h for magnetic materials in which the exchange interaction lifts the spin degeneracy. Recent experiments performed on Ni ballistic nanocontacts found a change of sign in the magnetoresistance obtained for the field parallel and perpendicular to the current. This behavior was interpreted and signature of AMR


The ballistic conductance is given by G=Ne2/h, where N is the number of open conducting channels. This quantity is affected by the spin-orbit interaction which is known to be much stronger in open and constrained geometries than in bulk materials. The effect is anisotropic because the orbital momentum is coupled to the spin causing its projection to be different depending on the magnetization direction. By changing the magnetization direction one can, therefore, change the number of bands crossing the Fermi energy and thereby affect the ballistic conductance.
4Â¥2013-03-15 08:12:37
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hookhans

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ÄûÃÊÊ÷: ½ð±Ò+30, ·­ÒëEPI+1, ¡ï¡ï¡ï¡ï¡ï×î¼Ñ´ð°¸, ¸øÄã¶àµÄ°É Èç¹û°æÖ÷´¦ÀíÁË ÎÒÔÙ¸øÄãÄǸöÌû×ÓµÄ Ð»Ð»¹þ 2013-03-15 09:16:30
1)        In such circumstances, the conductance is quantized with the unit 2e2/h for the non-magnetic materials. However, the unit for the magnetic materials should be e2/h due to lifting of the spin degeneracy by the exchange interaction. In recent study on the Ni ballistic nanocontacts, it was found that the magnetoresistance signal depends on whether the current and the magnetic field are parallel or perpendicular. Bu this kind of behavior was interpreted as the traditional signature of AMR.
2)        The ballistic conductance is given by the equation G=Ne2/h, where the number N is much strongly influenced by the spin-orbit interaction in nano-constrained geometries than that in a bulk material.  The coupling between self-spins and the orbital angular momentums results in anisotropic effects because it causes changes of the projection of the former (self-spin) with the magnetization direction. Therefore, the ballistic conductance can be tuned by fashioning (changing) the number of bands on the Fermi surface via. adjudgement of the  magnetization direction.
where-there-is-a-will-there-is-a-way.
5Â¥2013-03-15 09:01:58
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5Â¥: Originally posted by hookhans at 2013-03-15 09:01:58
1)        In such circumstances, the conductance is quantized with the unit 2e2/h for the non-magnetic materials. However, the unit for the magnetic materials should be e2/h due to lifting of the spin degen ...

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6Â¥2013-03-15 09:11:10
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