According to one embodiment, there is provided a spin torque oscillator including an oscillation layer formed of a magnetic material, a spin injection layer formed of a magnetic material and configured to inject a spin into the oscillation layer, and a current confinement layer including an insulating portion formed of an oxide or a nitride and a conductive portion formed of a nonmagnetic metal and penetrating the insulating portion in a direction of stacking. The conductive portion of the current confinement layer is positioned near a central portion of a plane of a device region including the oscillation layer and the spin injection layer.

Various methods for attaching a crystalline write pole onto an amorphous substrate and the resulting structures are described in detail herein. Further, the resulting structure may have a magnetic moment exceeding 2.4 Tesla. Still further, methods for depositing an epitaxial crystalline write pole on a crystalline seed or template material to ensure that the phase of the write pole is consistent with the high moment phase of the template material are also described in detail herein.