Development of method of high resolution magnetic imaging by spin polarized scanning tunneling microscope

自旋偏振扫描隧道显微镜高分辨率磁成像方法的发展

基本信息

批准号：
17560280
负责人：
UCHIDA Hironaga
金额：
$ 2.3万
依托单位：
Toyohashi University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17560280/
关键词：
Magnetic materials Surface Spin polarization Scanning tunneling microscope Ultra high vacuum スピン偏極走査トンネル顕微鏡磁性材料 STM 状態密度

项目摘要

We developed spin polarized scanning tunneling microscope (SP-STM) in order to investigate magnetic properties on surfaces with high resolution. First, we fabricated an ultra-high vacuum (UHV) system that consists of an analysis chamber and a preparation chamber; the analysis chamber equips an electromagnet with maximum magnetic field of 8 kOe, the STM and a low electron energy diffraction and auger electron spectroscopy (LEED/AES) system. The UHV system is evacuated by mechanical rotary pump, turbo molecular pump, ion pump and titanium sublimation pump; after baking this chamber at temperature of 150 degrees, vacuum pressure of lx10^<-8>0 Pa was obtained. The STM consists of a scanner of a tube piezo ceramics, a piezo motor for course approach, coil springs for anti-vibration, a sample holder and a pre-amplifier for measurement of tunneling current. ASTM tip is exchanged by using a wobble stick. Four STM tips and two samples are stored in a carousel inside the analysis chamber. We developed an STM controller with digital control method. A tunneling current flowing between tip and sample is converted by the pre-amplifier, and the obtained voltage is read by 16 bits AD converter, which is used for digital feedback to control the tip position from the sample. Scanning was achieved by applying triangular voltages to X and Y electrodes of the piezo scanner. For measuring spin polarized information, a rock in amplifier was used to detect AC components of the tunneling current. In order to fabricate sample of magnetic nano-structure for SP-STM measurements, fabrication by AFM anodization was performed on the permalloy Ni_<80>Fe_<20> thin film. In this study we developed the SP-STM. Hereafter, we will use this measurement system to obtain the surface magnetic information in nano-scale.

我们开发了自旋偏振扫描隧道显微镜 (SP-STM)，以便以高分辨率研究表面的磁性。首先，我们制造了一个超高真空（UHV）系统，由分析室和制备室组成；分析室配备最大磁场为8 kOe的电磁体、STM以及低电子能衍射和俄歇电子能谱（LEED/AES）系统。特高压系统采用机械旋转泵、涡轮分子泵、离子泵、钛升华泵抽真空；将该室在150度的温度下烘烤后，获得1×10^-80Pa的真空压力。 STM 由管压电陶瓷扫描仪、用于路线接近的压电电机、用于抗振的螺旋弹簧、样品支架和用于测量隧道电流的前置放大器组成。 ASTM 尖端通过使用摆动棒进行更换。四个 STM 吸头和两个样品存储在分析室内的转盘中。我们开发了一种采用数字控制方法的STM控制器。针尖与样品之间流动的隧道电流经前置放大器转换，获得的电压由16位AD转换器读取，用于数字反馈以控制针尖与样品的位置。通过向压电扫描仪的 X 和 Y 电极施加三角电压来实现扫描。为了测量自旋极化信息，放大器中的岩石被用来检测隧道电流的交流分量。为了制备用于SP-STM测量的磁性纳米结构样品，通过AFM阳极氧化在坡莫合金Ni_<80>Fe_<20>薄膜上进行制备。在这项研究中，我们开发了 SP-STM。今后，我们将利用该测量系统获取纳米尺度的表面磁信息。