Halley D, Bengone O, Boukari S, Weber W
Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, ULP - CNRS, 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2, France.
Phys Rev Lett. 2009 Jan 16;102(2):027201. doi: 10.1103/PhysRevLett.102.027201. Epub 2009 Jan 14.
A novel period of the interlayer exchange coupling as a function of Cr thickness is observed in epitaxial Fe/Cr/Fe (001) sandwiches capped with MgO. This additional period, equal to 3 chromium atomic layers, vanishes when the capping is Cr. A strong oscillation of the magnetic coupling is also observed as a function of the thickness of the Fe layer next to the MgO capping layer. This effect is attributed to the formation of quantum well states in this Fe layer. It is believed that this confinement modifies the reflection coefficient at the Cr/Fe interface for electrons of a particular symmetry and leads to the new coupling period which is linked to the Fermi surface topology of chromium.
在覆盖有MgO的外延Fe/Cr/Fe(001)三明治结构中，观察到层间交换耦合随Cr厚度变化的一个新周期。这个额外的周期等于3个铬原子层，当覆盖层为Cr时该周期消失。还观察到磁耦合随紧邻MgO覆盖层的Fe层厚度的强烈振荡。这种效应归因于该Fe层中量子阱态的形成。据信这种限制改变了特定对称性电子在Cr/Fe界面处的反射系数，并导致了与铬的费米面拓扑相关的新耦合周期。
