Magnetic effect and its application of functional pressure in permalloy keeper

当坡莫合金或铁氧体等软磁材料受到应力或外力刺激或作用时，磁导率会因畴壁运动的变化而逐渐或突然发生变化。我们尝试了这种现象，特别是不适（随着时间的推移渗透性逐渐降低）到牙科领域。目的有两个，一是分析磁性材料在同步或闭塞过程中的行为。二是对遮挡过程的分析。在这个实验中，磁性材料的前一种过程是有限的，因为许多观测结果都与此目的有关。此外，还发现光照射与磁导率松弛点（如失配）的机械力等效。这一原因可以从一种绝缘材料石榴石的光致畸变中得出。此外，在外部应力下发现了较大的巴尔克豪森效应。另一方面，通常的巴尔豪森效应由一个小的不连续的磁化步骤组成，其大小取决于重量的强度，导致晶体局部畸变。在实验初期，低温下石榴石发生光致失位的原因是一个令人困惑的问题。然而，我们提出了一种尝试性的解释，基于光致畸变和软材料中畴壁内诱导的优先方向产生局域电位最小值。随着时间的推移，这些最小值越深，畴壁的迁移率就会降低，这与退磁后初始渗透率的逐渐降低有关，即所谓的失配。

When the soft magnetic materials such as permalloy or ferrites including gar*ets are stressed, or under external stimulus or forces, the permeability is gradually or suddenly changed due to a change of domain wall movements. We tried the phenomena *pecially disaccommodation (gradual decrease of permeability with time) to the dentistry field. The objectives are double, one is the analysis of the behaviors of magnetic materials under simulus or occlusion process. The other is an analysis of occlusion process. In this experiment, the former process of magnetic materials is limited, since many obuservations are obtained in relation to this pourpose. Furthemore, light irradiation is found to be equivalent to the mechanical force in the point of the permeability relaxation such as disaccommodation. This reason may be drawn from the photoinduced distortion in an insulating materials, garnets. In addition, a large Balkhausen effect was found under external stress. On the other hands, a usual Balkhausen effect consists of a small discontinuous steps of magnetization, the magnitudes of which depend on the strength of weight, resulting in the crystal local distortion. In the preliminary stage of experiments, the reason why the photoinduced disaccommodation can take place in garnets at low temperatures is a puzzling problem. However, we propose a tentative explanation based on the photoinduced distortion and the induced preferred directions within the domain wall in soft materials create localized potential minima. As these minima become deeper with time, the mobility of the domain wall will decrease, associated with gradual decrease of initial permeability after demagnetization, so called, disaccommodation.