Sub-micrometer yttrium iron garnet LPE films with low ferromagnetic resonance losses
Sub-micrometer yttrium iron garnet LPE films with low ferromagnetic resonance losses
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DOI：
10.1088/1361-6463/aa6b1c
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发表时间：
2017-05-24
影响因子：
3.4
通讯作者：
Dellith, Jan
中科院分区：
文献类型：
--
作者：
Dubs, Carsten;Surzhenko, Oleksii;Dellith, Jan
使用液相外延（LPE）技术，在（1 1 1）钆镓石榴石（GGG）基板上生长了厚度约为100 nm、表面粗糙度低至0.3 nm的（1 1 1）钇铁石榴石（YIG）薄膜，作为微结构波导中自旋波传播实验的基本材料。连续应变薄膜表现出近乎完美的结晶度，没有明显的镶嵌性，并且有效晶格失配δ a(垂直于)/a(s)近似于10(-4)及以下。薄膜/基材界面极其尖锐，没有形成广泛的相互扩散层。所有 LPE 薄膜都表现出 (1800 +/- 20) Gs 的近块状饱和磁化强度和“易锥体”各向异性类型，具有极小的面内矫顽场 < 0.2 Oe。对于 < 1.5 Oe 的饱和场，观察到相当弱的面内磁各向异性，并具有明显的六重对称性。没有观察到显着的面外各向异性，但检测到有效磁化强度对晶格失配的弱依赖性。最窄的铁磁共振线宽确定为 1.4 Oe @ 6.5 GHz，这是迄今为止报道的厚度为 100 nm 及以下的 YIG 薄膜的最低值。所研究的 LPE 薄膜的吉尔伯特阻尼系数估计接近 1x10(-4)。
Using a liquid phase epitaxy (LPE) technique (1 1 1) yttrium iron garnet (YIG) films with thicknesses of approximate to 100 nm and surface roughnesses as low as 0.3 nm have been grown on (1 1 1) gadolinium gallium garnet (GGG) substrates as a basic material for spin-wave propagation experiments in microstructured waveguides. The continuously strained films exhibit nearly perfect crystallinity without significant mosaicity and with effective lattice misfits of Delta a(perpendicular to)/a(s) approximate to 10(-4) and below. The film/substrate interface is extremely sharp without broad interdiffusion layer formation. All LPE films exhibit a nearly bulk-like saturation magnetization of (1800 +/- 20) Gs and an 'easy cone' anisotropy type with extremely small in-plane coercive fields < 0.2 Oe. There is a rather weak in-plane magnetic anisotropy with a pronounced six-fold symmetry observed for the saturation field < 1.5 Oe. No significant out-of-plane anisotropy is observed, but a weak dependence of the effective magnetization on the lattice misfit is detected. The narrowest ferromagnetic resonance linewidth is determined to be 1.4 Oe @ 6.5 GHz which is the lowest value reported so far for YIG films of 100 nm thicknesses and below. The Gilbert damping coefficient for investigated LPE films is estimated to be close to 1x10(-4).