覆蓋超導層與氧化鎂位障對穿隧磁電阻之影響

Effect of capping superconductive layer and MgO spacer on tunnel magnetoresistance

林炳全(Bin-Chan Lin)

指導教授 ： 林敏聰

國立臺灣大學/理學院/物理研究所/碩士(2007年)

https://doi.org/10.6342/NTU.2007.03155

摘要

自旋穿遂磁電阻以鐵磁/絕緣/鐵磁所組成，在外加磁場下得到不同的
磁電阻，本文藉由改變自旋穿遂磁電阻的結構上以測量磁電阻的改
變，首先在自旋穿遂磁電阻上覆蓋一層鈮(50nm~100nm)，觀察當鈮進
入超導態時對磁電阻的影響，我們可以觀察到當鈮進入超導態時，磁
電阻的反平型態纂會隨著溫度而下降，而平型態電阻則不受影響。
再而在而我們改變穿遂層，由本來的氧化鋁改變成氧化鎂，並觀察加
熱後自旋穿遂磁電阻的電阻改變。

關鍵字

超導 ； 鈮 ； 氧化鎂 ； 穿遂 ； 磁阻

並列摘要

Magnetic tunnel junction is a promising candidate for applications in magnetic-storage technology, such as non-volatile memory, read head and magnetic sensors. Much higher tunnel magnetoresistance and lower resistance of junctions provide the feasibility for high-density magnetoresistive random-access-memory (MRAM) and less power consumption. We investgated the influence upon structure of magnetic tunnel junctions, including added capping layer and modification of spacer. We found that the TMR ratio drastically decreased with capping superconductive Nb. The thickness of capping Nb layer was varied onto TMR junctions to investgate the relation between superconductor and magnetism. Another TMR structure was examined on altering spacer. Huge TMR values have been theoretically predicted in (100) oriented single-crystalline Fe/MgO/Fe MTJs. We have fabricated MgO barrier layer which was sandwiched with amorphous CoFeB electrodes by magnetron supttering. We exhibit a well-defined parallel/antiparallel magnetic configuration by invoking Magneto-Optical Kerr Effect(MOKE), and adjust the thickness of MgO barrier to optimize TMR ratio. The annealing effect was also investigated to promote TMR value.

並列關鍵字

superconductor ； MTJ ； tunnel ； junction ； magnetoresistance

參考文獻

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