利用低溫自旋偏極化掃瞄穿隧電子顯微鏡解析垂直延展之面心立方結構錳(001)的層狀反鐵磁性自旋結構

Abstract

垂直延展之面心立方結構錳(001)薄膜已經被證實可以穩定的在鈷/銅(001)基板上成長，從磁光柯爾效應研究中，發現此系統的反鐵磁性特性，有隨著溫度及錳原子層厚度改變的相依性。並利用自旋偏極化掃瞄穿隧電子顯微鏡解析樣品表面原子自旋方向的技術，將可對此面心立方錳(001)的表面自旋結構，做出微小尺度上的研究。其方法為，將鎢探針鍍上四十層鐵原子層，使得探針尖端具有平行於樣品平面的磁異向能，如此便可從掃瞄穿隧電子顯微鏡的影像中，解析出平行於樣品平面分量的自旋結構，在低溫( 77.5 K )以及超高真空環境量測下，得到錳具有平行於樣品平面的層狀反鐵磁性自旋組態。另外我們在錳的表面接近原子台階邊緣的地方觀察到自旋翻轉，我們的微磁學模擬可以得到一致的結果。

Expanded face-centered tetragonal (e-fct) Mn (001) layers have been demonstrated to grow stably on Co/Cu(001) template. From the MOKE measurements, the antiferromagnetic properties of e-fct Mn has been studied through the behavior of the temperature and thickness dependence. In addition, with the surface spin sensitive techniques, spin-polarized scanning tunneling microscopy, the spin configuration on surface of such expanded-fct Mn(001) can be resolved. By using the 40 ML Fe coated W tip of in-plane magnetic anisotropy direction preference, the in-plane layered antiferromagnetic spin structures of e-fct Mn have been observed at the 77.5 K in ultrahigh vacuum environment. We observed the spin frustration phenomenon along the edge. The OOMMF simulation could obtain the consistent result.