Spin polarization of field-emitted electrons from Fe, Co, Ni, and rare-earth metals
Spin polarization of field-emitted electrons from Fe, Co, Ni, and rare-earth metals
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Fe、Co、Ni 和稀土金属场发射电子的自旋极化
DOI：
10.1103/physrevb.15.429
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发表时间：
1977
影响因子：
3.7
通讯作者：
R. Sizmann
中科院分区：
文献类型：
--
作者：
G. Chrobok;M. Hofmann;G. Regenfus;R. Sizmann
在10 K发射温度和6 T磁场强度下研究了场发射电子的自旋极化。场发射体是多晶材料的电解蚀刻的Fe、Co和Ni尖端以及通过气相沉积涂覆有Fe、Co、Ni和稀土的W尖端。未涂覆的W尖端未显示极化。到目前为止，Fe和Co的最大极化分别为+80%和+47%（+号表示占主导地位的多数自旋）。经常发现偏振在幅度上并且偶尔甚至在符号上变化超出控制，这取决于，例如，表面制备，发射点，尖端晶体学，吸附。清洁的Ni尖端在附近显示（-3.5 ± 1.5）%，在附近显示（0 ± 1.5）%。在这两种情况下，极化随着时间的推移增加到+15%的氢吸附。所有的铁磁稀土金属都具有相当高的电子自旋极化率，纯净的Gd可达+53%，EuO和EuS可达+90%。极化的温度依赖性大致遵循饱和磁化强度，如用Ni、Gd、EuO检查的。（AIP）
The spin polarization of field-emitted electrons is investigated at 10-K emitter temperature and magnetic field strengths up to 6 T. Field emitters are electrolytically etched Fe, Co, and Ni tips of polycrystalline material and W tips coated by vapor deposition with Fe, Co, Ni, and rare earths. Uncoated W tips show no polarization. The maximum polarization obtained so far is + 80% and + 47% for Fe and Co, respectively (the + sign indicates predominant majority spins). Often the polarization is found to vary beyond control in magnitude and occasionally even in sign, depending upon, e.g., surface preparation, emission spot, tip crystallography, adsorption. Clean Ni tips show (-3.5 +- 1.5) % in the vicinity of and (0 +- 1.5) % in the vicinity of . In both cases polarization increases with time up to + 15% by hydrogen adsorption. All ferromagnetic rare-earth metals give rather high electron spin polarization, clean Gd up to + 53%, EuO and EuS show up to + 90%. The temperature dependence of the polarization follows approximately the saturation magnetization, as checked with Ni, Gd, EuO. (AIP)