The Piezomagnetic Matteucci Effect in Nickel Alloys: Development of Theory and Applications

这个项目为Matteucci现象的描述奠定了基础。这项研究集中在一种相对简单的材料——坡莫合金上，它的磁致伸缩可以通过合金成分来控制。该项目包括样品制备，结构表征，以及在不同温度和磁场强度下扭转应力下磁性能变化的测量。这项工作将发展一个第一性原理，非线性，滞后，理论模型的现象。镍是提供一套可靠的基本数据的主要选择材料；与其他磁性材料相比，它具有较高的磁致伸缩、低的各向异性和对外加应力的高灵敏度等优点。此外，沿100和111方向的磁致伸缩系数具有可比性，从而使磁致伸缩对磁场的依赖更简单。镍可以与铁合金制成一系列磁致伸缩系数在+ 7ppm到- 35ppm之间的材料，从而可以测试响应对材料磁弹性性能的依赖关系。所有这些因素都是在寻找一个模型来描述观察到的材料行为的优势。这项工作将记录一个相对简单的磁系统在扭转应力作用下的行为，将检查这些材料在各种实验条件下对扭矩的磁响应，并将开发模型方程，帮助我们了解材料的性能。Matteucci效应，即材料在扭转应力作用下磁化强度的变化，由于对磁扭矩传感器材料的研究，目前在技术上引起了极大的兴趣。材料的磁性，特别是磁化，对应力非常敏感，但从科学的角度来看，人们对这种行为知之甚少。这是因为Matteucci效应是非线性和路径相关的（滞后）。目前还没有足够的理论可以用来准确地描述这种行为

This project lays the groundwork for a description of the Matteucci phenomenon. The research concentrates on one relatively simple class of materials known as permalloys in which magnetostriction can be controlled via the alloy composition. The project includes specimen preparation, structural characterization, and measurements of the changes in magnetic properties under torsional stress at different temperatures and magnetic field strengths. The work will develop a first principles, non-linear, hysteretic, theoretical model of the phenomenon. Nickel is the main material of choice for providing a reliable set of basic data; it has many advantages over other magnetic materials because of its relatively high magnetostriction, low anisotropy and high sensitivity to applied stress. In addition the magnetostriction coefficients along the 100 and 111 directions are comparable, resulting in a simpler dependence of magnetostriction on field. Nickel can be alloyed with iron to produce a series of materials with magnetostriction coefficients ranging from +7 ppm to -35 ppm, so that the dependence of the response on the magnetoelastic properties of the materials can be tested. All of these factors are an advantage in the search for a model to describe the observed behavior of the materials. This work will document the behavior of a relatively simple magnetic system under the action of torsional stress, will examine the magnetic response of these materials to torque under a variety of experimental conditions, and will develop model equations that help us to understand the performance of the material. %%%The Matteucci effect, that is the change of magnetization of a material with torsional stress, is currently of great technological interest because of the search for materials for magnetic torque sensors. Magnetic properties of materials, particularly magnetization, are very sensitive to stress, and yet this behavior is poorly understood from a scientific viewpoint. This is because the Matteucci effect is non-linear and path dependent (hysteretic). At present there is no adequate theory that can be used to accurately describe this behavior.***