Tunneling Magneto Resistance 

 

The electric resistance of a magnet-insulator-magnet multilayer depends on the relative orientation of the magnetic layers. Dimentions are a few nanometers. The goal is to understand the phenomenon with potential applications in magnetic field sensors, computer hard disks and memories.

The decay of the wavefunction in the gap of an insulator or semiconductor can be studied with the help of the complex bandstructure.

In case of perfect epitaxy, states of different symmetry decay differently in the gap. The decay constant (kappa) is given by the complex bandstructure which is shown red in the figure. 


From: Ph. Mavropoulos, N. Papanikolaou,  P.H. Dederichs, Phys. Rev. Lett. 85, 1088 (2000)

  Up