Domain structures and dynamics in Ferromagnetic shape memory materials: Theory and Experiment - Dynamic metallographic and magneto-optical polarization microscopy of MSMA systems

该项目是旨在了解磁性形状记忆材料中磁性和结构重取向过程的机制的联合合作的一部分。研究的目的是深入了解铁磁形状记忆合金(MSMA)的磁力学行为。我们研究这些样品的主要工具是光学偏振显微镜，它可以检测不同孪生变体的偏振对比度。我们还将使用磁光指示膜技术来探索磁畴结构。能够同时研究磁场和机械微结构，使我们能够研究这两种不同微结构的相互依赖和相互影响。研究将包括缓慢变化的磁场中的准静态过程，以及使用时间分辨率为几微秒的脉冲磁场进行更快的反转。调查还将包括研究不同温度的样品，以确定作用于孪生边界运动和迁移率的贡献效应。结果将为包中的理论小组提供有用的输入，以测试和完善他们在MSMA样品中的磁力学模型。此外，该项目广泛受益于与参与SPP 1239的其他准备和实验小组的强烈互动。

This project is part of a joint collaboration aiming at the understanding of the mechanisms of magnetic and structural reorientation processes in magnetic shape memory materials.The aim of the research is to obtain a deep insight into the magneto-mechanical behavior of ferromagnetic shape memory alloys (MSMA). Our main tool to investigate those samples is optical polarization microscopy, which can detect the polarization contrast of different twin variants. We will also explore the magnetic domain structure, using a magneto-optical indicator film technique. Being able to study both, the magnetic and mechanical microstructure, enables us to investigate interdependencies and mutual influences of the two different microstructures.The studies will include quasi-static processes in slowly changing magnetic fields and faster reversal using pulsed magnetic fields with temporal resolutions of the order of a few microseconds. The investigations will also incorporate studying the samples with varying temperatures in order to determine the contributing effects, which act on twin boundary motion and mobility.The results will provide useful input to the theory groups in the package to test and refine their models on the magneto-mechanics in MSMA samples.Moreover, the project extensively profits from the strong interaction with other preparational and experimental groups participating in the SPP 1239.