利用掃瞄探針顯微鏡探測鈷、鎳及鈷鎳複合奈米粒子

Abstract

摘要 本實驗目的在利用原子力顯微鏡(Atomic force Microscopy，AFM)及磁力顯微鏡(Magnetic force Microscopy，MFM)掃瞄Co、Ni及Co+Ni複合體奈米粒子的表面形貌與磁區觀察; Co、Ni及Co+Ni複合體奈米粒子由台北科技大學所研發的改良式真空潛弧法(Arc-Submerged Nanoparticle Synthesis System，ASNSS)製備，並經由乙二醇溶液保存著。筆者採取兩種不同的外加磁場方法，觀察奈米粒子在不同外加磁場方法下的AFM與MFM之表面形貌與磁區變化行為;接著利用原子力顯微鏡與磁力顯微鏡本身內建軟體，分析奈米粒子的Contrast difference of MFM signal。 利用磁力顯微鏡大氣系統在觀測上的優勢是:易於操作(不需抽真空)、解析度高，可看到樣品的表面形貌與最想觀測的磁區變化，搭配分析軟體可做Contrast difference of MFM signal的測量，並繼續利用Origin軟體作圖分析……等等。但是缺點在於真空度不佳，對於樣品表面的乾淨度不易維持，所以欲達到原子層級解析有困難，並且MFM的磁針只有三個月的壽命，必須趁探針尚有磁性的時候趕快測量，否則時間一過，就沒辦法量測出MFM圖形。另外，在掃MFM時容易遇到MFM模式常常掃不到磁區的情況，原因歸於有時候樣品的磁性變化不是那麼明顯，或是探針的磁性已經消磁等等。這是做實驗上遇到的最大困難度。此外，實驗上做Hemholtz線圈邊加磁場邊掃會容易受到磁場history的影響，也是實驗上會遇到的問題。 實驗結果顯示，排除MFM有時候不能掃到理想磁區的限制之外，磁力顯微鏡協助我們觀察Co、Ni及Co+Ni複合體奈米粒子在不同外加磁場方式下所呈現的結果，的確對我們不同的樣品量測MFM的優良與否判斷有其貢獻。結果發現，Co奈米粒子的MFM磁區最容易觀察，反之，Co+Ni奈米粒子最不容易觀察，Ni奈米粒子居於中間。Abstract This experimental purpose is to utilize an atomic force microscopy(AFM) and magnetic force microscopy(MFM) to survey the morphology and magnetic phenomenon of cobalt、nickel and cobalt with nickel compound nanoparticles.The cobalt、nickel and cobalt with nickel compound nanoparticles are manufactured by an arc-submerged nanoparticles synthesis system(ASNSS) which was researched and developed by Prof.Ho Chang’s group of National Taipei University of Technology. The cobalt、nickel and cobalt with nickel compound nanoparticles were collected in glycol liquids. I adopt different ways in adding magnetic field to samples ,and observed the morphology of AFM ,and the magnetic phenomenon of MFM of different ways of adding magnetic field to those nanoparticles. Then AFM and MFM software was used to analyze the Contrast difference of MFM signal of the nanoparticles。 The advantage of AFM in air system are to operate easier than in high vacuum system、observe the morphology and magnetic phenomenon of sample surface,use analytic software to measure the contrast difference of MFM signal、and continue using the Origion software to analysis the pictures 、etc.......But the shortcoming lies in the atomic resolution is unachieved because of low vacuity、hardly to maintain the clean of surface. Besides、the tip of MFM only has the lifetime of three months、after the three months、the magnetic property will disappear、so it can not measure the morphology of MFM. Otherwise、it is easier to measure nothing of the MFM images、because it is not so clear to see the phenomenon of magnetic property or the demagnetization of the tip. This is the most difficulties we met. The experimental results show that MFM images are helpful to distinguish the best magnetic phenomenon of cobalt、nickel and cobalt with nickel compound nanoparticles. So we find out it is the most easier to see the magnetic phenomenon of cobalt nanoparticles、and it is the hardest to see that of cobalt with nickel compound nanoparticles、and the nickel nanoparticles is in the middle.