摘要
采用气相沉积方法在硅油基底表面成功制备了一种具有近似自由支撑的新型铁薄膜系统,并研究了其生长机制、内应力分布以及低温磁特性.实验发现,此类铁薄膜的生长机制与沉积在液相基底表面非磁性薄膜的情况类似,即服从二阶段生长模型.在固定基底温度的条件下,当沉积速率较小时,可制得近似透明的连续铁薄膜,薄膜中呈现明显的特征尺寸达102μm数量级的带状准周期有序结构,它是由铁薄膜样品中内应力释放时所引起的薄膜板块间相互挤压而逐渐形成的.当沉积速率较大时,制得的连续铁薄膜呈金属色.实验发现,在临界温度Tc=10—15K附近,具有金属色的铁薄膜样品的矫顽力Hc有一明显的极大值峰.研究表明,这一奇异的矫顽力特性与液相基底表面铁薄膜中的原子团簇尺寸分布、无序的薄膜表面磁各向异性以及团簇间的磁性相互作用等因素有关.
An almost freely sustained new iron film system deposited on a silicone oil surface by vapor phase deposition has been fabricated, and its growth mechanism, internal stress patterns and low temperature magnetic properties have been studied. It is found that the growth mechanism obeys the two-stage growth model which was construed for non-magnetic film systems on liquid substrates. At a fixed substrate temperature and low deposition rate the iron films are almost transparent, and large ordered crack patterns with a characteristic length on the order of 10 2 μm are observed. Experiment shows that the ordered patterns result from the extrusion and alternate insertion of different pieces of iron film, due to the internal stress released in the nearly freely sustained film system. For higher deposition rates, however, the iron films exhibit a normal metallic color and the temperature dependence of the coercivity H c (T) of the films has a marked maximum peak around the critical temperature T c = 10—15 K. Our experimental results show that the anomalous magnetic properties are due to the non-uniform particle size distribution, random surface anisotropy and interparticle interactions in the films.
出处
《物理》
CAS
北大核心
2005年第5期362-370,共9页
Physics
基金
国家自然科学基金(批准号:10174063)
浙江省青年人才专项基金(批准号:1997-RC9603)资助项目
