• 作者： 張慶瑞; 柯松仁
• 作者服務機構： 台灣大學物理學系; 中央研究院物理研究所
• 中文摘要： 磁性物質的磁滯特性乃是由於其有多個暫穩態而產生的。熱弛緩效應使得每一暫穩態都有一定的生命期，這也同時決定了磁性物質的功用。我們將綜論磁性物質內的熱激發過程的最新發展，由熱弛緩理論探討磁動力學、單磁區的翻轉與磁壁的結合與釘扎。利用基礎的原理來研究磁性物質的實用現象對熱激發的響應，如磁滯力、翻轉場分佈、磁黏滯、磁化率等。我們同時也會討論宏觀穿隧效應的問題及相關的實驗結果。
• 英文摘要： Magnetic materials are distinguished by the presence of multiple metastable states which cause themto have hysteresis properties. However, the ubiquitous thermal relaxation effects cause these states tohave a finite lifetime whose length ultimately determines the technical applicability of the material Weoffer here a survey of thermally activated processes in magnetic materials. This survey is prefaced bya brief exposition of the theory of thermal relaxation, and we proceed then to discuss stochastic mag-netization dynamics, magnetization reversal in single domain particles, and domain wall nucleation andunpinning. The properties of these fundamental physical processes are then used to explain the observedmanifestations of thermal activation, and for a wide range of magnetic materials we discuss such phenomenaas coercivity, switching field distribution, magnetic viscosity, susceptibility etc. This work contains acomprehensive bibliography, and due to its current interest, we also discuss the macroscopic quantumtunneling of magnetization.
• 中文關鍵字： magnetic anisotropy and hysteresis; thermal relaxation and stochastic dynamics; magnetic viscosity; coherent rotation of magnetization; domain wall mucleation and unpinning; macroscopic quantum tunneling
• 英文關鍵字： --