Spintronics Breakthrough: Negative Resistance of a Single Magnetic Domain Wall
Date: Thursday, September 02, 2004 @ 20:54:21 MST
"Spintronics Breakthrough: Negative Resistance of a Single Magnetic Domain Wall Measured" - September 02, 2004
Physicists for several years have been predicting a new age of semiconductor devices that operate by subtle changes in the orientation of electron spins. Known as "spintronics," the field relies on an intricate knowledge of the magnetic properties of materials and of how magnetic moments can be manipulated.
Now, scientists at the California Institute of Technology have developed a novel method of measuring the resistance of "domain walls," which are the nanoscale boundaries separating areas of a magnetized material that possess different magnetic alignments, or a "twist" of magnetic spins...
This work also resolves an issue that has puzzled scientists for some time, according to Tang. Many physicists have thought that domain walls were a natural barrier to electron transport and that they cause positive resistance--in other words, the magnetic moments with different alignments created a natural opposition to the flow of charge from one side of the wall to the other. However, the new results show that the resistance is actually negative, which can be attributed to quantum effects in the locale of the domain wall itself. The very fact that the resistance is negative means that electrons can flow more easily under certain conditions, manifesting quantum mechanical origin in this novel phenomenon...
Read the whole article at: http://www.physorg.com/news1043.html