Tunable 0-π transition by spin precession in Josephson junctions

We study the electrical control of 0-pi transition in Josephson junctions with a ferromagnet/two-dimensional electron gas (2DEG)/ferromagnet coupling layer. There is Rashba spin-orbit coupling in the 2DEG and the three layer structure is a Datta-Das spin transistor. When electrons or holes travel through the 2DEG layer, their spins are rotated by the spin-orbit coupling, which is equivalent to varying the angle between the magnetizations of the two ferromagnetic layers and thus leading to a 0-pi transition. We show that the 0-pi transition can be fully controlled by tuning the strength of spin-orbit coupling. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3425764]