Doppler broadening of annihilation radiation measurements on 3d and 4f ferromagnets using polarized positrons
Doppler broadening of annihilation radiation measurements on 3d and 4f ferromagnets using polarized positrons
复制标题
使用极化正电子对 3d 和 4f 铁磁体进行湮没辐射测量的多普勒展宽
DOI：
10.1103/physrevb.85.024417
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发表时间：
2012
影响因子：
3.7
通讯作者：
et al.
中科院分区：
文献类型：
--
作者：
A. Kawasuso;et al.
我们使用来自 aGe-Ga 源的自旋极化正电子测量了磁场下（Fe、Co 和 Ni）和（Gd、Tb 和 Dy）铁磁体的湮没辐射 (DBAR) 谱的多普勒展宽。结果表明，这些金属的 DBAR 光谱具有显着不同的磁场依赖性。 Fe、Co和Ni之间的差异反映了Fe和Co的上部少数自旋能带几乎为空，而Ni的上部少数自旋能带仍然大部分被占据。对于稀土金属而不是内电子，介导电子交换相互作用的电子主要负责磁场对 DBAR 谱的影响。此外，磁场对 Gd、Tb 和 Dy 的 DBAR 光谱的影响在这些金属磁相变的居里温度以上消失。
We measured the Doppler broadening of annihilation radiation (DBAR) spectra of(Fe, Co, and Ni) and(Gd, Tb, and Dy) ferromagnets under a magnetic field by using spin-polarized positrons from aGe-Ga source. The results showed that the DBAR spectra of these metals have notably different magnetic-field dependences. The differences among Fe, Co, and Ni reflect that the upper minority spin bands of Fe and Co are nearly empty while those of Ni are still mostly occupied. For the rare-earth metals instead of the innerelectrons,electrons that mediate the exchange interaction of theelectrons are primarily responsible for the magnetic-field effects on the DBAR spectra. Furthermore, the magnetic-field effects on the DBAR spectra of Gd, Tb, and Dy vanished above the Curie temperatures of the magnetic-phase transition for these metals.