送交者: 材科小生 于 2006-5-29, 16:39:06:
"""""科学家利用磁性半导体制出新型自旋电子学元件
磁体实验室中Jagadeesh Moodera领导的这个小组发明的磁性半导体材料是氧化铟，其中掺入了少量的铬。这种材料放置在传统的硅半导体表面，带有确定自旋方向的电子通过硅注入进去。自旋极化的电子在半导体中运动，并且被线路另一端的自旋探测器读取。
虽然这种新材料本身就是一项非常重要的发明，但是Moodera说，更重要的突破是他们证明了材料的磁性与周期排布的原子中的缺陷或空穴有关。这个因果关系是以前不知道的。Moodera的研究小组通过控制原子层次上的缺陷，可以在很宽的范围内调节材料的磁性。"""
我对稀磁领域有点了解.看过他们发表在Nature Nature上的论文.其实他们并不是第一做In2O3搀杂磁性离子观察到磁性的.人家做的早,还只发论文到Applied Physics Letters上,他在牛校,是牛人，关系好,就上 NM.
另外,他们只是观测到稀磁现象,根本没有制作器件.最搞笑的是,牛人居然说"It sits on top of a conventional silicon semiconductor, where it injects electrons of a given spin orientation into the semiconductor. The spin-polarized electrons then travel through the semiconductor and are read by a spin detector at the other end of the circuit. "
自旋电子是硅中来的???实际上,他们NM中的论文,材料是长在SiO2/Si上的,有一层绝缘的SiO2,怎么注入???
实际上,稀磁半导体的研究,目前是一潭混水.外界铁磁污染,假象,搀杂Fe, Co, Ni, Cr造成的第二相,都是能造成磁信号的原因.而自旋电子器件的制作需要载流子相关的本征磁性.
总之有关稀磁的论文是一大堆,但是应用前途非常暗淡!
英文原文见: (http://www.physorg.com/news67701686.html)
The magnetic semiconductor material created by Moodera's team is indium oxide with a small amount of chromium added. It sits on top of a conventional silicon semiconductor, where it injects electrons of a given spin orientation into the semiconductor. The spin-polarized electrons then travel through the semiconductor and are read by a spin detector at the other end of the circuit.
Although the new material is promising in itself, Moodera says the real breakthrough is their demonstration that the material's magnetic behavior depends on defects, or missing atoms (vacancies), in a periodic arrangement of atoms. This cause-and-effect relationship was uncertain before, but Moodera's team was able to tune the material's magnetic behavior over a wide range by controlling defects at the atomic level.