Development of point-contact spectrometer for spin polarization measurements
Development of point-contact spectrometer for spin polarization measurements
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开发用于自旋偏振测量的点接触光谱仪
DOI：
10.1088/1742-6596/897/1/012001
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
T. Kawae
中科院分区：
文献类型：
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作者：
M. Shiga;N. Nishimura;H. Takata;Y. Inagaki;H. Kambara;K. Tenya;T. Kawae
我们构造了一个用于自旋极化测量的针砧式点接触谱仪，它安装在4He低温恒温器中。两种类型的压电装置用于精确控制样品铁磁体和超导体之间的接触尺寸。安装了一个基于attocube压电的定位器，用于尖端的粗移动，而堆叠式压电装置用于接触尺寸的精细控制。这使得能够将针尖和样品之间的接触尺寸从亚微米连续地改变为原子尺寸的接触。通过抑制进入样品空间的热流和机械振动，我们可以在数小时内保持接触，从而实现精确测量。为了检验光谱仪的性能，我们研究了多晶SrRuO3的自旋极化与点接触Andreev反射测量。在界面的清洁极限处，极化估计为0.59，这与先前的研究一致。
We construct a “needle-anvil” type point-contact spectrometer for spin polarization measurements, which is installed in a 4He-cryostat. Two types of piezo devices are used to control the contact size precisely between a sample ferromagnet and a superconductor. An attocube piezo-based positioner is mounted for coarse movement of the tip, while a stacked-type piezo device is used for fine control of the contact size. This enables to change the contact size between the tip and sample from sub micro-meters to atomic-size contacts continuously. By suppressing thermal flow into the sample space and mechanical vibration, we can keep the contact over hours, enabling the precision measurements. To examine the performance of the spectrometer, we study the spin polarization of polycrystalline SrRuO3 with the point-contact Andreev reflection measurements. The polarization is estimated to be ∼0.59 at the clean limit of the interface, which is consistent with previous study.