【摘要】： YBCO高溫超導(dǎo)帶材具有優(yōu)異的電學(xué)性能,它具有在外場(chǎng)下臨界電流高,交流損耗低以及成本較低等優(yōu)點(diǎn),在工業(yè)應(yīng)用中有非常大的潛力,所以各國(guó)都投入了巨大的人力物力進(jìn)行研究。直流濺射具有方法簡(jiǎn)單、易于控制以及工藝重復(fù)性好等特點(diǎn),本文基于直流濺射法研究了Y2O3種子層薄膜的制備工藝,并且在制備有Y2O3/YSZ/CeO2 (YYC)緩沖層的鎳鎢合金(Ni-5at.%W)基帶上制備YBCO涂層導(dǎo)體進(jìn)行了研究,還對(duì)YBCO薄膜的磁通釘扎特性也做了初步探討。主要內(nèi)容如下: 1、根據(jù)c軸擇優(yōu)度和溫度的關(guān)系以及反應(yīng)濺射特有的遲滯效應(yīng),得出當(dāng)溫度為720℃,濺射電流為0.2A,水分壓為0.016Pa,反應(yīng)濺射處于平衡狀態(tài),制備出Y2O3種子層薄膜純c軸取向,且面內(nèi)面外半高寬為3.9°和4.9°。 2、在Y2O3/YSZ/CeO2(YYC)緩沖層上制備YBCO涂層導(dǎo)體,發(fā)現(xiàn)緩沖層表面粗糙度對(duì)YBCO薄膜的性能有很大的影響,分別在反應(yīng)濺射法和射頻濺射法制備YYC緩沖層上以相同的工藝制備YBCO薄膜,兩種緩沖層都是純c軸取向,面內(nèi)面外取向一致性相當(dāng),但反應(yīng)濺射法制備的緩沖層粗糙度明顯大于射頻濺射制備的,在前者上制備的YBCO薄膜臨界電流密度Jc為1.2 MA/cm2,而在后者基礎(chǔ)上制備的YBCO薄膜的臨界電流密度Jc達(dá)到2.8 MA/cm2。 3、探討了用卷繞法在平面靶直流濺射裝置上連續(xù)制備YBCO帶材的工藝,780℃為卷繞法制備YBCO薄膜的適宜溫度,由于平面靶的負(fù)離子反濺射效應(yīng)較為明顯,綜合考慮靶基距和氣體總壓,并且通過(guò)改變卷繞速度,補(bǔ)償由于負(fù)離子反濺射效應(yīng)導(dǎo)致的成分偏差,在靶基距為20mm,氣體總壓為70Pa,卷繞速度為0.55m/h時(shí),臨界電流密度達(dá)到0.6MA/cm2。 4、研究了YBCO超導(dǎo)薄膜在磁場(chǎng)下的性能變化,首先在65K和77K的溫度下,外加0-2T的磁場(chǎng)下對(duì)未摻雜的YBCO薄膜的性能進(jìn)行測(cè)試,磁場(chǎng)方向垂直于基片表面,溫度越低,YBCO薄膜的性能隨磁場(chǎng)強(qiáng)度的增大下降的趨勢(shì)越弱,然后我們還用Y過(guò)量的靶制備了富Y的YBCO薄膜,由于Y2O3在YBCO薄膜中形成釘扎中心,其在磁場(chǎng)下的性能明顯優(yōu)于未摻雜的YBCO薄膜。
[Abstract]:YBCO high temperature superconducting strip has excellent electrical properties. It has the advantages of high critical current, low AC loss and low cost in external field. It has great potential in industrial application. So many countries have invested huge manpower and material resources to study. DC sputtering has simple method, easy control and good process repeatability. In this paper, the preparation process of Y2O3 seed layer films was studied based on DC sputtering, and the preparation of YBCO coated conductors on the base band of nickel tungsten alloy (Ni-5at.%W) with Y2O3/YSZ/CeO2 (YYC) buffer layer was studied. The magnetic flux pinning properties of the YBCO film were also discussed. The main contents are as follows:
1, according to the relationship between the optimum degree and the temperature of the c axis and the specific hysteresis effect of the reactive sputtering, it is obtained that when the temperature is 720, the sputtering current is 0.2A, the water pressure is 0.016Pa and the reactive sputtering is in the equilibrium state, the pure c axis orientation of the Y2O3 seed layer film is prepared, and the outer surface half width of the surface is 3.9 and 4.9 degrees.
2, to prepare the YBCO coated conductor on the Y2O3/YSZ/CeO2 (YYC) buffer layer, it is found that the surface roughness of the buffer layer has a great influence on the performance of the YBCO film. The YBCO film is prepared by the same process in the reaction sputtering and the RF sputtering preparation of the YYC buffer layer respectively. The two buffer layers are pure c axis orientation, and the in-plane orientation consistency is equal, but it is quite consistent. The roughness of the buffer layer prepared by reactive sputtering is obviously greater than that of RF sputtering. The critical current density of the YBCO film prepared on the former is 1.2 MA/cm2, while the critical current density of the YBCO thin film prepared on the basis of the latter reaches 2.8 MA/cm2..
3, the process of continuous preparation of YBCO strip on a DC sputtering device by a winding method is discussed. The suitable temperature of YBCO film is prepared by winding method at 780 C. Because the negative ion sputtering effect of the plane target is more obvious, the target base distance and the total gas pressure are taken into consideration, and the negative ion sputtering effect is compensated by the change of the winding speed. The composition deviation is caused by a critical current density of 0.6MA/cm2. when the target base distance is 20mm, the total gas pressure is 70Pa, and the winding speed is 0.55m/h.
4, the performance changes of the YBCO superconducting film under the magnetic field are studied. First, at the temperature of 65K and 77K, the performance of the undoped YBCO film is tested under the magnetic field of the 0-2T. The direction of the magnetic field is perpendicular to the surface of the substrate. The lower the temperature is, the weaker the performance of the YBCO film decreases with the increase of the magnetic field strength, and then we also use the target of Y excess. The Y rich YBCO thin films were prepared. Because Y2O3 forms a pinning center in YBCO films, its performance in magnetic field is much better than that in undoped YBCO films.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2010
【分類(lèi)號(hào)】：TM26

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本文編號(hào)：2150625