Fabrication and properties of nanoscale magnets

Shinjo的研究小组利用电子束光刻系统制备了磁性纳米线，并通过电阻率测量研究了畴壁的动态行为。样品具有磁性/非磁性/磁性层的三明治结构，并且通过由于非耦合GMR效应引起的电阻率变化来观察每层中的磁化反转。在以前的结果中，观察到的开关场不是唯一的，但有一个显着的分布。通过由非磁性元素（Cu）制备端子部分，切换场变为可再现值，因此畴壁成核得到令人满意的控制。如果焊盘附着在导线的一端，则在焊盘中开始的反转成核和开关场意味着畴壁从颈部进入导线部分的势垒。在胶体、Shinjo和Miyajima群中尝试了10 nm范围内的超窄线的制备，并研究了极低温下的电阻率。Miyazima等人观察到了点接触的量子化现象，Takahashi等人研究了在极其清洁的气氛中制备的薄膜的特性。Matsui等人研究了穿过氧化物阻挡层的隧道结。Katayama和Ookoshi研究了钴点的各向异性和Cu/Co薄膜的异常磁性。

Shinjo's group has prepared magnetic nanowires by using an e-beam lithography system and studied the dynamic behaviors of domain walls from electric resistivity measurements. Samples have a sandwich structure with magnetic/non-magnetic/magnetic layers and magnetization reversals in each layer are observed by the resistivity change due to the non-coupled GMR effect. In former results, the observed switching field was not unique but has a significant distribution. By preparing the terminal parts from a non-magnetic element (Cu), the switching field becomes a reproducible value and therefore the domain wall nucleation is controlled satisfactorily. If a pad is attached at one end of the wire, the nucleation of reversal initiated in the pad and the switching field means the potential barrier for the domain Wall to enter the wire part from the neck. Preparation of ultranarrow wires in the region of 10nm are attempted in the colloboation and Shinjo and Miyajima groups and the electric resistivity in very low temperatures are studied. The quantization phenomena at point contacts are observed by Miyazima et al. Takahashi et al. examined the features of films prepared in an extremely clean atmosphere. Matsui et al. studied the tunnel junctions through oxide barriers. Katayama and Ookoshi investigated the anisotropy of cobalt dots and anomalous magnetic properties of Cu/Co films.