Collaborative research: Testing a new empirical law relating the efficiency of thermoremanent magnetization (TRM) and saturation magnetization (Ms)

这项工作正在测试一个新的经验标度定律，该定律表明，热残余磁化（TRM）的获取效率表现出低功率场依赖性，根据饱和磁化M(s)对不同材料进行偏移（Kletetschka et al. 2004）。新结果最引人注目的方面是，该定律适用于钛磁铁矿从单畴到多畴的畴态范围。因此，尽管许多最初的样品是大的和多域的，磁铁矿的结果表明，该定律可能具有普遍的适用性。研究岩石中的标度规律的第一个关键问题是合成样品和岩石中颗粒分布的退磁因子(N)的性质。N在弱场磁化率的讨论中最常遇到，在弱场磁化率中，表观磁化率可以通过退磁效应强烈地控制。由于退磁因素是采集过程的重要组成部分，因此在已知退磁因素的岩石中确定颗粒分布的TRM和IRM。所需要的关键观察是测试幂律对于已知消磁因子的精细粒子的良好控制分布。考虑到现代磁力计的灵敏度，这可以用相对较小和可控数量的粒子来完成。它们将在显微镜下进行检查，并分散在高温水泥和制备的“玻片”中。最初，交互被避免了，但最终将生成带有交互的分布。利用强磁场对分散体进行排列，相对于强磁场，样品可以保持静止或旋转。然后用光学和扫描电子显微镜重新检查最终的合成样品。然后给出各个领域的ARM和TRM，并通过irm进行归一化分析。用经典标准双加热方法对合成样品和现有主要岩石样品进行了IRMs归一化估计的古强度比较。我们的结果显示了IRMs规范化方法的可能用途，并提供了深入研究分析所基于的基本规律主题的动机。NRM， ARM， v IRMs图绝不是选择适合古强度观测的样品的唯一方法。然而，它们是非常简单的数据，易于阅读。热磁化（TRM）是古地磁记录最重要的载体之一，因此建立一个令人信服的热磁化模型对地球物理和行星物理学具有重要意义。这样一个简单的经验规律描述了TRM的获取效率，是非常了不起的。月球磁学中最有趣的结果之一来自于这一想法的应用，而在陨石磁学中其他可能的应用也有很大的希望。这项工作是本科生工作的一个很好的研究领域。有一种相对常规的测量，因此它们不会被必要的实验室技术所淹没。然而，学生们知道必须仔细测量。学生最终也会学到很多基本的实验室技术和一些实用的电磁学。

This work is testing a new empirical scaling law showing that the efficiency of acquisition of Thermal Remanent Magnetization (TRM) exhibits a power low field dependence, with offsets for different materials according to the saturation magnetization M(s) (Kletetschka et al. 2004). The most remarkable aspect of the new results is that the law holds over the range of domain states from single domain to multidomain for titanomagnetite. Thus, although many of the initial samples were large and multidomain, the results from magnetite suggest that the law may have universal application. The first key problem in investigating the scaling law in rocks is the nature of the demagnetizing factor (N) of distributions of particles in synthetic samples and rocks. N is most often encountered in discussions of weak field susceptibility, where the apparent susceptibility can be strongly controlled by demagnetizing effects.Because the demagnetizing factor is such an important part of the acquisition process, TRM and IRM in distributions of particles is being determined in rocks whosedemagnetizing factors are known.The key observations that are required are to test the power law for well-controlled distributions of fine particles whose demagnetization factors are known. Given the sensitivity of modern magnetometers, this can be done using relatively small and controllable number of particles. They will be examined microscopically and dispersed in high temperature cement and "slides" prepared. Initially, interactions are being avoided, but eventually distribution with interactions will be generated. The dispersions are being aligned using strong magnetic fields, relative to which the sample can be kept stationary or rotated. The final synthetic samples are then reexamined with optical and scanning electron microscopy. ARM and TRM are then being given in a variety of fields and the analysis by IRMs normalization carried out.Comparison of the paleointensity estimates from IRMs normalization is done with classical standard double heating methods for the synthetic samples and the major collection of rocks available.Our results show possible uses of the IRMs normalization method and provide motivation to delve deeper in to the topic of the fundamental law that the analyses are based upon. The NRM, ARM, v IRMs plots are by no means the only means of selection of samples for suitability for paleointensity observations. However, they are quite simply obtained data and easy to read. Thermoremanent Magnetization (TRM) is one of the most important carriers of the paleomagnetic record and therefore to develop a convincing model of it has ramifications for geophysics and planetary physics. Such a simple empirical law describing the efficiency of acquisition of TRM is very remarkable. One of the most intriguing results in lunar magnetism came from an application of this idea and other possible applications in the magnetism of meteorites hold major promise. This work is in an excellent research area for undergraduate work. There are measurements of a relatively routine kind, so that they are not overwhelmed by the necessary laboratory techniques. Yet students learn that the measurements must be made carefully. Students also eventually learn plenty of basic laboratory techniques and some practical electromagnetism.