The highly nonlinear coupling of transport and magnetic properties in a
multiwell heterostructure, which comprises ferromagnetic quantum wells made of
diluted magnetic semiconductors, is theoretically investigated. The interplay
of resonant tunneling and carrier-mediated ferromagnetism in the magnetic wells
induces very robust, self-sustained current and magnetization oscillations.
Over a large window of steady bias voltages the spin polarization of the
collector current is oscillating between positive and negative values,
realizing a spin oscillator device.Comment: 3 pages, 4 figure
