hcp－Niおよびhcp-NiFe薄膜のエピタキシャル成長

摘要

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 hep crystals consist of two types of (1120)_(hcp) domains whose c-axes are in plane and rotated around the film normal by 90° each other. The hep 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 hep 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 hep crystals.%分子線エビタキシー法によりAu（100）単結晶下地層上にエビタキシヤルN iおよびNiFe薄膜を形成し，構造と磁気特性を調べた．hcp-N i結晶およびbcp－NiFe結晶がそれぞれ基板温度300℃以下および400℃以下で形成された．いずれの場合もhcp結晶はc軸が膜面と平行でしかも互いに90°回転した方位関係を持つ2タイプの（1120）_(hcp)バリアントから構成された・基板温度の上昇に伴い，準安定なhcp結晶はより安定な触結晶に変態する傾向が認められた．基板温度100℃で形成したN iおよびNiFe薄膜は主にhcp結晶から構成されていることが分かった．hcp-N iおよびhcp-NiFe薄膜はそれぞれバルクfcc－N iおよびfcc-NiFe結晶とほぼ同程度の飽和磁化値を持ち，bcp＜0001＞方向に磁化容易軸を持つ磁気異方性を示した．