论文标题
在超快X射线衍射探测的gadolinium铁石榴石异质结构中的低温纳米级热传输
Low-temperature nanoscale heat transport in a gadolinium iron garnet heterostructure probed by ultrafast x-ray diffraction
论文作者
论文摘要
时间分辨X射线衍射已用于测量PT/GD3FE5O12 // GD3GA5O12金属/氧化物异质结构的低温热传输特性与旋转热量量货币的应用相关。脉冲的飞秒光学信号在PT层中会迅速升高，然后加热到GD3FE5O12（GDIG）薄膜和GD3GA5O12（GGG）底物中。使用基于加速器的飞秒X射线源跟踪GDIG层X射线衍射的时间依赖性。超快衍射测量值探测了放牧X射线衍射几何形状中GDIG（1 -1 2）X射线反射的强度。衍射X射线强度与模型的变化的比较，包括热传输和GDIG晶格参数的温度依赖性，允许确定PT/GDIG和GDIG // GGG接口的热电导率。 GDIG层的低温热膨胀特性的互补同步加速器X射线衍射研究提供了GDIG晶格参数的温度依赖性的精确校准。根据时间分辨衍射研究确定的PT/GDIG和GGG接口的界面热电导率与以前关于金属/氧化物和外延介电介质接口的报道的数量级相同。 PT/GDIG的热参数// GGG异质结构将有助于设计和实施热传输设备和纳米结构。
Time-resolved x-ray diffraction has been used to measure the low-temperature thermal transport properties of a Pt/Gd3Fe5O12//Gd3Ga5O12 metal/oxide heterostructure relevant to applications in spin caloritronics. A pulsed femtosecond optical signal produces a rapid temperature rise in the Pt layer, followed by heat transport into the Gd3Fe5O12 (GdIG) thin film and the Gd3Ga5O12 (GGG) substrate. The time dependence of x-ray diffraction from the GdIG layer was tracked using an accelerator-based femtosecond x-ray source. The ultrafast diffraction measurements probed the intensity of the GdIG (1 -1 2) x-ray reflection in a grazing-incidence x-ray diffraction geometry. The comparison of the variation of the diffracted x-ray intensity with a model including heat transport and the temperature dependence of the GdIG lattice parameter allows the thermal conductance of the Pt/GdIG and GdIG//GGG interfaces to be determined. Complementary synchrotron x-ray diffraction studies of the low-temperature thermal expansion properties of the GdIG layer provide a precise calibration of the temperature dependence of the GdIG lattice parameter. The interfacial thermal conductance of the Pt/GdIG and GdIG//GGG interfaces determined from the time-resolved diffraction study is of the same order of magnitude as previous reports for metal/oxide and epitaxial dielectric interfaces. The thermal parameters of the Pt/GdIG//GGG heterostructure will aid in the design and implementation of thermal transport devices and nanostructures.
