Properties of spin transport of double quantum rings with structures of ferromagnet/semiconductor/ferromagnet

Spin-dependent transport through ferromagnetic/semiconductor/ferromagnetic double quantum rings is studied in this paper. It is found that the average value of the spin-dependent electron transmission coefficient of the double quantum ring is larger than that of the single quantum ring under the condition of zero magnetic flux and antiparallel configration of the ferromagnetic electrodes. When the magnetization directions of the ferromagnetic electrodes are parallel, the average tunneling coefficient of the spin-down electrons in double quantum rings increases distinctly. When the Rashba spin-orbit coupling is considered, the average tunneling coefficient of the spin electrons in double quantum rings is bigger than that in single quantum ring. The applied magnetic field enhences the tunneling coefficient. The delta barrier of the double quantum rings suspresses the tunneling of the electron. The tunneling coefficient decreases monotonically and nonlinearly with the delta barrier strength Z increasing.