MgO单晶势垒磁性隧道结的第一性原理计算和实验研究

PROGRESS ON FIRST-PRINCIPLES CALCULTIONS AND EXPERIMENTAL RESULTS OF SINGLE-CRYSTALLINE MAGNETIC TUNNEL JUNCTIONS WITH MgO BARRIERS

在MgO单晶势垒磁性隧道结中发现的室温高隧穿磁电阻现象,是近些年自旋电子学以及磁性隧道结磁电阻材料研究中的又一重大突破。本文主要评述和介绍2001年以来MgO单晶势垒磁性隧道结第一性原理计算和实验上的重要进展,以及介绍利用Layer-KKR第一性原理计算方法研究的Fe(001)/MgO/Fe、Fe(001)/FeO/MgO/Fe、Fe(001)/Mg/MgO/Fe、Fe(001)/Co/MgO/Co/Fe和Fe(001)/MgO/Fe/MgO/Fe等基于单晶MgO(001)单势垒及双势垒磁性隧道结材料的电子结构和自旋相关输运性质研究的最新进展。这些第一性原理定量计算的结果,不仅从物理上增强了对MgO单晶势垒磁性隧道结的电子结构和自旋相关输运特性的了解,而且对于研究新型室温磁电阻隧道结材料及其在自旋电子学器件中的广泛应用,具有一定的参考价值。

Since the theoretical prediction and experimental observation of giant tunneling magnetoresistance （TMR） effect at room temperature in magnetic tunnel junctions （MTJs） with single- crystalline MgO （001） barrier, MgO-based MTJs have been extensively studied due to their broad potential applications in spintronic devices. In this paper, progress on theoretical calculations and experimental results in MgO-based MTJs is reported. Spin-dependent electronic structure and transport properties of MgO-based MTJs, including structures of Fe （001）/MgO/Fe, Fe （001）/FeO/MgO/Fe, Fe （001）/Mg/MgO/Fe, Fe （001）/Co/MgO/Co/Fe, and Fe （001）/MgO/Fe/MgO/Fe, have been studied using the Layer-KKR method. The quantitative result not only provides a better way to understand the electronic structures and spin-dependent transport properties of MgO-based MTJs, but also shows a direction to, exploit new kinds of spintronic materials with high room-temperature TMR ratio.