文章信息/Info

Title:

Exchange Couplings in Magnetic Films

作者:

劉偉; 劉雄華; 龔文杰; 郭盛; 張志東

 (中國科學院金屬研究所，遼寧 沈陽 110016)

Author(s):

LIU Wei;  LIU Xionghua;  GONG Wenjie;  GUO Sheng;  ZHANG Zhidong

(1. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China)

關鍵詞:

磁性交換耦合; 交換偏置; 磁各向異性; 磁輸運; 磁性多層膜

DOI:

10.7502/j.issn.1674-3962.2013.06.01

文獻標志碼:

A

摘要:

介紹了在磁性薄膜材料中的交換耦合的研究進展。制備了鐵磁/反鐵磁/鐵磁3層結構不同成分的薄膜。利用X射線粉末衍射（XRD）、掃描電鏡（SEM）、透射電鏡（TEM）等測試分析技術，系統研究了磁性多層薄膜的相組成、界面及微觀結構等。利用超導量子干涉儀（SQUID）研究薄膜的磁、電性能和交換耦合。在Co/反鐵磁/Fe結構中發現了非常明顯的與溫度相關的鐵磁/反鐵磁界面耦合與鐵磁/鐵磁層間耦合之間的競爭效應。含有不同鐵磁層Fe、Co、Fe����20�狽i����80��的3層膜FM��1/Cr��2O��3/FM��2對交換耦合隨溫度的變化存在較強的影響，發現鐵磁層的磁晶各向異性和跟Cr��2O��3接觸的自旋非對稱性反射系數體系的界面和層間耦合有很大的影響。鐵磁層對FM/AFM的交換耦合強度的影響甚大，這種影響和鐵磁層的各向異性的相關性要強于和鐵磁層飽和磁化強度的相關性。通過面內預加場和場冷的方式，在易軸互相垂直的［Pt/Co］���玭��/NiFe/NiO異質結中實現了交換偏置的4種狀態，可等溫調控偏置。研究了Co/NiO反點陣列和連續膜的交換偏置，與連續膜相比，納米反點陣列既能增大偏置，也能減小偏置，具有更高的熱穩定性。��

Abstract:

 This article introduces recent advances in study of exchange couplings in magnetic films. The Ferromagnetic(FM)/Antiferrromagnetic(AF)/Ferromagnetic(FM) trilayers are prepared by magnetron sputtering. Component, interface and microstructure of magnetic films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), et al. Magnetic and magnetotransport properties were characterized by superconducting quantum interference device (SQUID). The competition between interlayer and interfacial exchange couplings is found to be temperature dependent in Co / AF / Fe trilayers. The strong effects of ferromagnetic materials on exchange couplings are observed at different temperatures in FM1/Cr2O3/FM2 trilayers with FM ? Co, Fe or Ni80Fe20. The changes of anisotropy of FM and spin-asymmetry of the reflection coefficients for FM contacted antiferromagnetic layer greatly influence the strengths of interfacial and interlayer couplings of the trilayers. Strong effects of ferromagnetic layers on exchange coupling of FM/AF bilayer are observed, which are related to anisotropy of FM more strongly than saturation magnetization. Through magnetic field cooling and applying set magnetic field, four states of exchange bias have been achieved in [Pt/Co]/NiFe/NiO heterostructures with orthogonal easy axes, and also the isothermal tunable exchange bias has been obtained. The exchange bias in the Co/NiO antidot arrays and continuous films has been investigated. Compared with the continuous films, an enhanced or decreased exchange bias field and a higher thermal stability have been found in the antidot arrays.