Physical Interpretation of Hysteresis Measurements through Numerical Simulation

ToxeEAR-0229498磁滞测量已成为古地磁研究中表征岩石磁性行为的重要组成部分。由于矿物磁性的复杂性，理论解释往往很困难，已公布的数据集展示了目前尚不能解释的剩磁和矫顽力行为。在过去的十年里，数值微磁模型被用来模拟磁性粒子。这种模拟揭示了单磁区和多磁区之间存在非均匀的剩余态，即所谓的“花”和“涡”构型。这为许多磁滞测量提供了可信的解释，但不能解释高饱和剩磁、高矫直力数据，如在细粒海底玄武岩中常见的数据。微磁模型有望为大范围的磁滞行为提供合理的解释。研究人员建议将他们的数值模拟扩展到更多不同的形状和大小，包括粒子的随机组合和比简单的杆状和立方体更复杂的形状。他们还将探索室温磁铁矿以外的重要磁性材料的参数空间。最后，他们将把热波动纳入他们的数值代码中，并扩大建模工作的范围，以包括这一非常重要的影响。

TauxeEAR-0229498Hysteresis measurements have become an important part of characterizing magnetic behavior of rocks in paleomagnetic studies. Theoretical interpretation is often difficult owing to the complexity of mineral magnetism and published data sets demonstrate remanence and coercivity behavior that is currently unexplained. In the last decade numerical micromagnetic modelling has been used to simulate magneticparticles. Such simulations reveal the existence of non-uniform remanent states between single and multi-domain, known as the "flower'' and "vortex'' configurations. These suggest plausible explanations for many hysteresis measurements yet fall short of explaining high saturation remanence, high coercivity data such as those commonly observed in fine grained submarine basalts. Micromagnetic modelling promises to provide plausible explanations for a wide range of hysteresis behavior. The investigators propose to extend their numerical simulations to a greater variety of shapes and sizes, including random assemblages of particles and shapes more complex than simple rods and cubes. They also will explore the parameter space of important magnetic materials other than room temperature magnetite. Finally, they will incorporate thermal fluctuations into their numerical code and expand the scope of modelling efforts to include this very important effect.