Magnetic properis of Cr2AlC(Mn) thin films

薄膜形式的MAX相由于其结合了独特的金属和陶瓷性质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，它具有很高的抗氧化性和耐损伤性。Cr2AlC的磁性能既没有实验研究，也没有理论研究。从我们自己的工作中，我们知道Cr2AlC层的磁性能强烈依赖于相的结构（固溶体或有序的纳米层状结构）。该联合应用的一个重要目标是定量确定沉积膜和热降解（氧化）后的膜生产参数、结构和磁性之间的关系。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，该方法可用于帮助描述MAX相薄膜在生产后（在质量控制方面）和使用后（在控制层的条件方面）的状态。考虑到这一点，这项工作的进一步目标是提高转变温度，目前在低温范围内，到室温。通过在Cr2AlC MAX相中掺杂Mn，可以达到这一目的。实验工作将得到热力学计算的支持和比较。本文的进一步目标是利用理论预测和实验证据来控制Cr2AlC MAX相的磁性能，从而使其在更高温度下超越保护层的使用谱，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.