添加Ru元素於Cr底層對Cr/CoCrPtTaB水平記錄媒體之微結構與磁性質的影響

Abstract

本實驗研究了添加元素於雙膜層Cr/CoCrPtTaB水平記錄媒體之底層對其微結構與磁性質的影響。首先，我們固定磁性層厚度在500Å而改變底層厚度從150Å∼600Å，探討底層添加Ru與否對微結構與磁性質的影響。接著挑出磁性質較穩定的底層條件，進行固定底層厚度在500Å，改變磁性層厚度從100Å∼500Å，探討Cr底層添加Ru與否對磁性質的影響。 我們利用直流磁控濺鍍法在康寧玻璃基板上製作所有的試片，待鍍製好的試片完成之後，拿去作成分分析、結構鑑定、微結構觀測與磁性量測。X-ray diffraction的繞射峰顯示，Cr底層添加Ru元素之後會造成Cr(200)晶面的向低角度偏移，證實了部分Ru原子以取代型固溶體的形式存在於Cr晶格內。經plane-view TEM影像的晶粒計算，發現Cr(250Å)/CoCrPtTaB(500Å)在Cr底層添加10 at％Ru之後，磁性層晶粒可由118Å縮小到103Å；Cr(500Å)/CoCrPtTaB(500Å)在Cr底層添加10 at％Ru之後，磁性層晶粒可由112Å縮小到54Å；高解析cross-section TEM影像中，介面的觀察證實了介面間原子的堆疊方式為磊晶成長；而高解析plane-view TEM影像可觀察到水平磁記錄媒體雙膜層結構下的“織構線”。磁性量測方面，發現底層厚度增厚Hc會有增大的趨勢，又底層添加Ru元素系列其Hc增大的情形更明顯；接著Mrt的計算結果，顯示底層不管添加Ru與否並不會造成此數值的多大變動，其範圍均落在0.25∼0.35 memu/cm2之間。接著將Cr底層添加Ru的量從0 at％∼15 at％作改變，發現矯頑磁力與Mrt數值均隨Ru添加量越多而有上升之趨勢。

In this thesis, we investigated the effect of microstructure and magnetic properties by doping Ru into Cr underlayer of Cr/CoCrPtTaB longitudinal recording media. At first, the thickness of magnetic layer were fixed at 500Å, and that of underlayer were changed from 150Å to 600Å. We discuss the effect of microstructure and magnetic properties after doping Ru into underlayer. Then, we choose a stable condition on magnetic property for further experiment. The thickness of underlayer layer were fixed at 400Å, and that of magnetic layer were changed from 100Å to 500Å. All samples were made by dc magnetron sputtering on corning glass substrate. After depositing samples, we did composition analysis, structure identification, microstructure observation, and magnetic properties measurement for them. By X-ray diffraction, the peak of Cr(200) shift to low angle after Ru doping into Cr underlayer. It can be verified that some Ru atoms exist in Cr lattice site as substitutional solid solution. Grain size calculation in plane-view TEM images, after doping Ru into underlayer of Cr(250Å)/CoCrPtTaB(500Å) and Cr(500Å) /CoCrPtTaB(500Å) grain size can be reduced from 118Å to 103Å and from 112Å to 54Å, respectively. In high resolution cross-section TEM observation, we can verify that atomic stacking in interface is epitaxial growth. In high resolution plane-view TEM images, we can observe “texture line” in bi-layer structure of longitudinal recording media. By magnetic properties measurement, coercivity can be enhanced by increasing thickness of underlayer, especially Cr9Ru1 underlayer. Mrt calculating results indicated that underlayer with Ru or not won’t make an effective influence, and the value of Mrt is always fall into the range of 0.25 – 0.35 memu/cm2.Then, coercivity and Mrt product will increase with the increasing of Ru doping into Cr underlayer from 0 to 15 at%.