Gadolinium makes good spin contacts

A junction between silicon and a ferromagnetic metals have the significant advantage of being non-volatile and can be used to bring together non-volatile magnetic storage and conventional electronics. The abundance of inexpensive silicon and well-established facilities for its fabrication makes it the leading material candidate for developing future spin-logic devices compatible with existing electronics. Injected spins in silicon are weakly coupled to their environment and the flipping of the spin's direction is relatively slow, which would enable significant improvements in several classes of proposed spin transistors. The spin imbalance at room temperature can be maintained over a long distance and a long time compared with other conventional semiconductors. Two approaches are usually pursued to introduce spin-polarized carriers in semiconductors, one is controlled doping with magnetic impurities and spin injection or transfer from a neighboring spin-polarized material.