Magnetic properis of Cr2AlC(Mn) thin films

最近，薄膜形式的MAX相由于其结合了金属和陶瓷特性的独特混合的晶体结构而引起了越来越多的关注。Cr2AlC是最有前途的MAX相之一，它具有很好的抗氧化性和损伤容忍性。以前对Cr2AlC的磁性既没有从实验上也没有从理论上进行过研究。从我们自己的工作中得知，Cr2AlC层的磁性能强烈依赖于相的结构(固溶体或有序纳米层状结构)，这一联合应用的一个重要目标是定量地确定薄膜的制备参数、结构和磁性能之间的关系，无论是沉积时还是热降解(氧化)后的薄膜。必须研究磁性能随生产和老化过程的变化，以便能够开发一种可能的测量方法，该方法可以用于描述MAX相薄膜在生产后(在质量控制方面)和在使用后(在控制层条件方面)的状态。考虑到这一点，这项工作的另一个目标是将目前处于低温范围的转变温度提高到室温。这可以通过在Cr2AlC MAX相中掺入Mn来实现。实验工作将得到热力学计算的支持，并与之进行比较。该方案的另一个目标是利用理论预测和实验证据来控制Cr2AlC Max相的磁性，从而将其使用谱增加到更高温度下的保护层之外，朝着功能层的方向发展。

MAX phases in the form of thin films have recently attracted increased attention due to their crystal structure which combines a unique blend of metallic and ceramic properties. Cr2AlC is one of the most promising MAX phases for which a very good combination of high oxidation resistance and damage tolerance is obtained. The magnetic properties of the Cr2AlC have been neither experimentally nor theoretically previously investigated. From our own work it is known that the magnetic properties of the Cr2AlC layers are strongly dependent on the structure of the phase (solid solution or ordered nano-laminated structure).An important goal of this joint application is a quantitative determination of the relationships between the film production parameters, the structure and magnetic properties both of as deposited films and after thermal degradation (oxidation). The changes of the magnetic properties with the production and ageing process must be investigated in order to be able to develop a possible measurement method which can be used to help describe the state of the MAX phase thin films after production (in terms of quality control) and after use (in terms of controlling the condition of the layer). With this in mind a further goal of this work is to raise the transition temperature, which at the moment is in cryogenic temperature range, to room temperature. It is proposed that this will be achieved by doping of the Cr2AlC MAX phase with Mn. The experimental work is to be supported by and compared with thermodynamic calculations. A further goal of the proposal is to use the theoretical prediction and experimental evidence in order to control the magnetic properties of the Cr2AlC MAX phase and, thereby, increase its usage spectrum beyond that of a protective layer at higher temperatures in the direction of being a function layer.