Hirohata Atsufumi, Frost William, Samiepour Marjan, Kim Jun-Young
Department of Electronic Engineering, University of York, York YO10 5DD, UK.
Department of Physics, University of York, York YO10 5DD, UK.
Materials (Basel). 2018 Jan 11;11(1):105. doi: 10.3390/ma11010105.
For the sustainable development of spintronic devices, a half-metallic ferromagnetic film needs to be developed as a spin source with exhibiting 100% spin polarisation at its Fermi level at room temperature. One of the most promising candidates for such a film is a Heusler-alloy film, which has already been proven to achieve the half-metallicity in the bulk region of the film. The Heusler alloys have predominantly cubic crystalline structures with small magnetocrystalline anisotropy. In order to use these alloys in perpendicularly magnetised devices, which are advantageous over in-plane devices due to their scalability, lattice distortion is required by introducing atomic substitution and interfacial lattice mismatch. In this review, recent development in perpendicularly-magnetised Heusler-alloy films is overviewed and their magnetoresistive junctions are discussed. Especially, focus is given to binary Heusler alloys by replacing the second element in the ternary Heusler alloys with the third one, e.g., MnGa and MnGe, and to interfacially-induced anisotropy by attaching oxides and metals with different lattice constants to the Heusler alloys. These alloys can improve the performance of spintronic devices with higher recording capacity.
为了实现自旋电子器件的可持续发展，需要开发一种半金属铁磁薄膜作为自旋源，使其在室温下的费米能级处表现出100%的自旋极化。这种薄膜最有前途的候选材料之一是赫斯勒合金薄膜，该薄膜已被证明在其体区能够实现半金属性。赫斯勒合金主要具有立方晶体结构，磁晶各向异性较小。为了将这些合金用于垂直磁化器件（由于其可扩展性，垂直磁化器件比平面内器件更具优势），需要通过引入原子替代和界面晶格失配来产生晶格畸变。在这篇综述中，概述了垂直磁化赫斯勒合金薄膜的最新进展，并讨论了它们的磁阻结。特别关注的是通过用第三种元素取代三元赫斯勒合金中的第二种元素而得到的二元赫斯勒合金，例如MnGa和MnGe，以及通过将具有不同晶格常数的氧化物和金属附着到赫斯勒合金上而产生的界面诱导各向异性。这些合金可以提高具有更高记录容量的自旋电子器件的性能。
