發(fā)布時(shí)間：2019-04-24 10:53

【摘要】：本文主要研究了CoFeB薄膜和TbFeCo薄膜樣品,探索了這些薄膜的制備工藝參數(shù),分析了薄膜的磁、磁光、磁電和結(jié)構(gòu)特性。本文主要研究內(nèi)容展開如下:首先,利用磁控濺射系統(tǒng)制備了結(jié)構(gòu)為Ta/CoFeB/MgO/Ta的樣品,系統(tǒng)研究了CoFeB薄膜水平磁各向異性和結(jié)構(gòu)特性。以不同功率濺射制備了CoFeB合金薄膜樣品并在高真空下退火處理。觀察到低功率生長的薄膜始終具有磁各向同性,而高功率生長的薄膜隨著退火溫度的升高,由起始的單軸磁各向異性逐漸向磁各向同性轉(zhuǎn)變。X射線衍射分析也印證了CoFeB薄膜隨退火溫度的升高,薄膜由非晶態(tài)逐漸向晶態(tài)轉(zhuǎn)變。觀察到低功率生長的CoFeB的(110)峰值高于高功率生長的樣品峰值,表明低功率生長的薄膜晶粒尺寸更大。同時(shí),當(dāng)退火溫度高于400℃時(shí),低功率生長的CoFeB樣品的矯頑力大于高功率生長薄膜的矯頑力。隨后,研究了沉積態(tài)下磁性層厚度對薄膜磁特性的影響,結(jié)果表明薄膜隨著磁性層厚度的增加,薄膜面內(nèi)磁各向異性由弱到強(qiáng)再到弱的變化規(guī)律,且在磁性層厚度為36 nm時(shí)薄膜的面內(nèi)磁各向異性達(dá)到最大。其次,制備了結(jié)構(gòu)為Ta/Pd/CoFeB/MgO/Ta的樣品,系統(tǒng)研究了CoFeB薄膜垂直磁各向異性。觀察到退火時(shí)間、磁性層厚度和MgO厚度對CoFe B薄膜垂直磁各向異性具有較大的影響。在研究退火時(shí)間對CoFeB薄膜反常霍爾效應(yīng)影響時(shí),選取磁性層厚度為1.6 nm,MgO厚度為1.8 nm,薄膜在退火30 min處理時(shí),薄膜垂直磁各向異性最優(yōu)。在研究磁性層厚度時(shí),選取CoFeB薄膜厚度區(qū)間為1.0 nm到2.0 nm,觀察到薄膜都具有優(yōu)良的垂直磁各向異性,且CoFe B厚度為1.6 nm時(shí),薄膜具有最大矯頑力。在研究MgO層厚度時(shí),選取MgO層厚度區(qū)間為0.6 nm到3.0 nm,結(jié)果表明薄膜矯頑力隨MgO層厚增加出現(xiàn)先增大后減小現(xiàn)象。然后,利用鑲嵌靶技術(shù),制備了結(jié)構(gòu)為Ta/TbFeCo/Ta的樣品,系統(tǒng)研究了TbFeCo薄膜的磁學(xué)性質(zhì)和結(jié)構(gòu)特性。在研究濺射功率對薄膜特性的影響時(shí),結(jié)果表明沉積的TbFeCo薄膜為非晶結(jié)構(gòu),通過改變?yōu)R射功率,實(shí)現(xiàn)薄膜在富TM狀態(tài)和富RE狀態(tài)之間過渡。在研究薄膜厚度對TbFeCo薄膜磁電和磁光效應(yīng)影響時(shí),結(jié)果表明富FeCo狀態(tài)下的TbFeCo薄膜矯頑力隨著薄膜厚度的增加而增加,同時(shí)驗(yàn)證了反常霍爾電壓和薄膜厚度成反比關(guān)系。最后,根據(jù)已有的實(shí)驗(yàn)結(jié)果,以具有垂直磁各向異性的CoFeB薄膜和非晶TbFeCo薄膜,中間用MgO層將兩磁性層隔開,簡單的制備了結(jié)構(gòu)為Ta/Pd/CoFeB/MgO/TbFeCo/Ta多層膜。經(jīng)過退火處理后,CoFeB層和TbFeCo層在不同的外磁場條件下發(fā)生了連續(xù)磁化翻轉(zhuǎn)。
[Abstract]:In this paper, the samples of CoFeB and TbFeCo films have been studied. The preparation parameters of these films have been explored. The magnetic, magneto-optical, magnetoelectric and structural properties of the films have been analyzed. The main contents of this thesis are as follows: firstly, samples with Ta/CoFeB/MgO/Ta structure were prepared by magnetron sputtering system. The horizontal magnetic anisotropy and structural properties of CoFeB thin films were studied systematically. CoFeB alloy thin films were prepared by sputtering with different power and annealed in high vacuum. It is observed that the films grown at low power are always magnetically isotropic, while the films grown at high power are characterized by the increase of annealing temperature. From the initial uniaxial magnetic anisotropy to the magneto-isotropic transformation, X-ray diffraction analysis also confirmed that the CoFeB thin film changed from amorphous state to crystalline state with the increase of annealing temperature. It was observed that the (110) peak of low power growth CoFeB was higher than that of high power growth sample, indicating that the grain size of low power grown film was larger than that of high power growth sample. At the same time, when the annealing temperature is higher than 400 鈩，

本文編號：2464390