Multilayered Si/Ni nanosprings and their magnetic properties

A two-turn, eight-armed, rectangular Si/Ni heterogeneous nanospring structure on Si(100) has been fabricated using a multilayer glancing-angle deposition technique. The multilayered nanosprings with a height of approximate to 1.98 mu m were composed of alternating layers of amorphous Si nanorods approximate to 580 nm in length and face-centered cubic Ni nanorods approximate to 420 nm in length, both with a diameter of approximate to 35 nm. The magnetic anisotropy of the nanosprings showed that the in-plane easy and hard axes were parallel and perpendicular to the Ni nanorod plane, respectively. The out-of-plane magnetic hysteresis loop was very sensitive to the applied magnetic field direction when rotating the nanosprings about their in-plane hard axis, and the magnetization measurement revealed that the nanosprings tilted at approximate to 7.5 degrees toward the plane of the Si nanorods. The magnetic anisotropy of the nanosprings is determined by their structure, and the experimental results can be interpreted by the shape anisotropy energy.