Epitaxial Growth of hcp-Ni and hcp-NiFe Thin Films
Details
Ni and NiFe epitaxial thin films were prepared on Au(100) single-crystal underlayers by molecular beam epitaxy. The structural and the magnetic properties were investigated. hcp-Ni and hcp-NiFe crystals are obtained at temperatures lower than 300℃ and 400℃, respectively. The both kinds of hcp crystals consist of two types of (112^^-0)_<hcp> domains whose c-axes are in plane and rotated around the film normal by 90° each other. The hcp crystals tend to transform into more stable fcc crystals during film growth process with increasing the substrate temperature. X-ray diffraction and high-resolution transmission electron microscopy show that the Ni and the NiFe films prepared at 100℃ consist primarily of hcp crystals. The saturation magnetization values of hcp-Ni and hcp-NiFe films are similar to those of bulk fcc-Ni and fcc-NiFe crystals. The in-plane magnetization properties of hcp-Ni and hcp-NiFe films are interpreted to be reflecting the magnetocrystalline anisotropies of bulk hcp crystals.
