Magnetism and spin transport in rare-earth-rich epitaxial terbium and europium iron garnet films
Magnetism and spin transport in rare-earth-rich epitaxial terbium and europium iron garnet films
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DOI：
10.1103/physrevmaterials.2.094405
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发表时间：
2018-09
影响因子：
3.4
通讯作者：
E. Rosenberg;L. Beran;C. Avci;C. Zeledon;B. Song;Claudio Gonzalez-Fuentes;J. Mendil;P. Gambardella-P.-Gam
中科院分区：
文献类型：
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作者：
E. Rosenberg;L. Beran;C. Avci;C. Zeledon;B. Song;Claudio Gonzalez-Fuentes;J. Mendil;P. Gambardella-P.-Gam
具有垂直磁各向异性（PMA）的稀土铁石榴石薄膜近年来在自旋电子学中的应用引起了广泛的关注。成功地生长了铥铁石榴石（TmIG），并对TmIG/Pt异质结构进行了表征。然而，TmIG并不是唯一可以用PMA生长的稀土铁石榴石。我们报道了外延铽铁石榴石（TbIG）和铕铁石榴石（EuIG）薄膜的生长、磁性和自旋电子特性。互反空间映射表明，即使薄膜厚度达到56 nm，薄膜也与衬底晶格匹配，没有应变松弛。晶格应变和磁致伸缩系数在某些情况下产生PMA。TbIG生长在（111）钆镓石榴石（GGG）上，由于PMA的面内压缩应变，而TbIG生长在（111）取代GGG （SGGG）上，处于拉伸状态，具有面内易轴。EuIG与PMA一起生长在（100）和（111）GGG衬底上，这有助于研究自旋电子性质作为取向的函数。两种石榴石都含有过量的稀土，认为稀土占据了铁八面体的位置，在TbIG的情况下，与补偿温度升高到330 K有关，高于体值。Pt/EuIG霍尔交叉的反常霍尔效应（AHE）测量表明，Pt/(111)和（100）EuIG的自旋混合电导相似。Pt/TbIG Hall交叉的AHE测量显示补偿点的AHE振幅有明显变化，类似于全金属系统。
Rare-earth iron garnet thin films with perpendicular magnetic anisotropy (PMA) have recently attracted a great deal of attention for spintronic applications. Thulium iron garnet (TmIG) has been successfully grown and TmIG/Pt heterostructures have been characterized. However, TmIG is not the only rare-earth iron garnet that can be grown with PMA. We report the growth, magnetic, and spintronic properties of epitaxial terbium iron garnet (TbIG) and europium iron garnet (EuIG) thin films with PMA. Reciprocal space mapping shows the films are lattice matched to the substrate without strain relaxation, even for films up to 56 nm thick. The lattice strain and magnetostriction coefficient produce PMA in certain cases. TbIG grows on (111) gadolinium gallium garnet (GGG) with PMA due to the in-plane compressive strain, whereas TbIG on (111) substituted GGG (SGGG) is in tension and has an in-plane easy axis. EuIG grows with PMA on (100) and (111) GGG substrates, which facilitates the investigation of spintronic properties as a function of orientation. Both garnets have excess rare earth, which is believed to occupy Fe octahedral sites and in the case of TbIG is associated with an increase in the compensation temperature to 330 K, higher than the bulk value. Anomalous Hall effect (AHE) measurements of Pt/EuIG Hall crosses show that the spin mixing conductance of Pt/ (111) and (100) EuIG is similar. AHE measurements of Pt/TbIG Hall crosses reveal a sign change in the AHE amplitude at the compensation point analogous to all-metallic systems.