In order to enhance the storage density of information in the magnetic storage devices, scientists pay most attention to develop the novel magnetic materials that possessing magnetoresistance (MR). In most of them, the giant magnetoresistance (GMR) has been extensively explored in magnetic memory and logic devices for which the spin degree of freedom dominates the mechanism of manipulation. The major challenge for spintronics is how to enhance the density of spin-polarized currents for transforming information. Half metals are recommended as the best candidates for spin-based electronics, possessing highly spin-polarized electrons.