脉冲激光沉积法制备Mn-Co-Ge-Si薄膜的研究
Study on the Synthesis of Mn-Co-Ge-Si Thin Films via Pulsed Laser Deposition Technique

Mn-Co-Ge基块体合金具有优异的磁热性能，但由于磁结构耦合特性，导致在进行磁热转换时合金块材容易发生碎裂。将块材样品制备成薄膜状态是目前提高其韧性的重要手段之一。本文采用脉冲激光沉积技术制备出Mn-Co-Ge-Si薄膜样品，研究衬底种类以及热处理工艺等因素对薄膜晶体结构以及表面形貌的影响。实验结果表明，Mn-Co-Ge-Si薄膜可在具有同样六方结构的蓝宝石Al₂O₃衬底上择优取向生长，且薄膜表面平整致密。该薄膜磁热材料的成功制备拓宽了磁热材料在磁制冷领域的应用范围。
Mn-Co-Ge-based alloys show excellent magnetocaloric effects, but accompanying serious weakness, that is the break-up of the samples during the phase transitions due to magnetostructural coupling. Fabricating thin films rather than bulk samples has been proved to be an effective way to overcome this weakness at present. This work reports the deposition of Mn-Co-Ge-Si thin films using the pulsed laser deposition technique. The effect of substrate categories and annealing treatment on the crystal structure and morphology of the films was investigated. The results reflect that Mn-Co-Ge-Si thin films with a dense and uniform surface show textured growth on sapphire Al₂O₃ substrate having a similar hexagonal structure. The successful fabrication of the films widens the range of applications of magnetocaloric materials in the magnetic refrigeration field.