CEMES CNRS-UPR 8011, Université de Toulouse , 31055 Toulouse, France.
INSP CNRS-UMR 7588, Sorbonne Universités-UPMC 75252 Paris, France.
Nano Lett. 2017 Apr 12;17(4):2460-2466. doi: 10.1021/acs.nanolett.7b00144. Epub 2017 Mar 22.
Most studies on MnAs material in its bulk form have been focused on its temperature-dependent structural phase transition accompanied by a magnetic one. Magnetostructural phase transition parameters in thin MnAs films grown on substrates present however some differences from the bulk behavior, and local studies become mandatory for a deeper understanding of the mechanisms involved within the transition. Up to now, only surface techniques have been carried out, while the transition is a three-dimensional phenomenon. We therefore developed an original nanometer scale methodology using electron holography to investigate the phase transition in an epitaxial MnAs thin film on GaAs(001) from the cross-section view. Using quantitative magnetic maps recorded at the nanometer scale as a function of the temperature, our work provides a direct in situ observation of the inhomogeneous spatial distribution of the transition in the layer depth and brings new insights on the fundamental transition mechanisms.
大多数关于块状 MnAs 材料的研究都集中在其伴随磁性的温度相关结构相变上。然而，在衬底上生长的 MnAs 薄膜的磁结构相变参数与块状行为存在一些差异，因此需要进行局部研究以更深入地了解相变过程中的机制。到目前为止，只进行了表面技术的研究，而相变是一个三维现象。因此，我们开发了一种原创的纳米尺度方法，使用电子全息术从横截面观察 GaAs(001)上外延 MnAs 薄膜中的相变。通过在纳米尺度上记录定量的磁图谱作为温度的函数，我们的工作提供了对层深中相变不均匀空间分布的直接原位观察，并为基本相变机制提供了新的见解。
