本文選題：Cr基超導　切入點：Mn基超導　出處：《陜西師范大學》2015年碩士論文

【摘要】：最近發(fā)現的高壓下CrAs和MnP的超導電性,使CrAs和MnP分別成為Cr基和Mn基第一個超導體化合物,這一發(fā)現在超導領域引起了巨大的反響。CrAs和MnP的體超導電性出現在一個反鐵磁量子臨界點附近,暗示了非常規(guī)的超導配對機制。然而很多揭示超導微觀機制的實驗手段很難在高壓下進行。因此嘗試用化學摻雜的方法探索兩個體系中更多可能的超導電性,實現Cr基和Mn基化合物的常壓超導,對研究CrAs和MnP的非常規(guī)超導電性非常重要。本文的研究工作在此基礎上展開。本文首次利用助熔劑法成功制備出摻雜的CrAs和MnP0.8B0.2單晶樣品,并對CrAs1-xPx和MnP0.8B0.2單晶樣品進行了系統的低溫物性研究,最后與CrAs和MnP高壓下的實驗結果進行比較。本文主要由以下三部分構成：第一部分首先介紹了CrAs單晶的基本物性和高壓下CrAs的超導電性。隨后首次報道了CrAs1-xPx單晶樣品的電阻率和比熱實驗數據。低溫下正常態(tài)電阻率和電子比熱系數γ的行為,說明在臨界摻雜量x=0.05附近存在一個量子臨界點,此時CrAs的長程磁有序已被完全壓制掉。這與CrAs高壓下的行為相似。但在2K以上沒有觀測到超導。第二部分首先介紹了高壓誘導的MnP超導電性。隨后首次報道了MnP0.8B0.2單晶樣品的電阻率、比熱和磁化率數據。Mn0.8B0.2單晶樣品的磁矩很小,表現出強的磁各向異性。在低溫下,MnP0.8B0.2中存在很強的磁阻效應。MnP0.8B0.2在100K以下處于傾斜反鐵磁態(tài)或螺旋磁有序態(tài)。MnP0.8B0.2的低溫正常態(tài)電阻率與MnP加壓4-6GPa時的行為非常相似。德拜溫度和MnP基本一樣,而態(tài)密度相比MnP有明顯增加。第三部分總結目前所做的工作,提出未解決的問題和未來的可行性研究方向。
[Abstract]:The recently discovered superconductivity of CrAs and MnP at high pressure makes CrAs and MnP the first superconductor compounds based on Cr and mn respectively. This discovery has caused great repercussions in the field of superconductivity. CRAs and MnP's bulk superconductivity appears near an antiferromagnetic quantum critical point. However, many experimental methods to reveal the microcosmic mechanism of superconductivity are difficult to carry out at high pressure. Therefore, we try to explore more possible superconductivities in the two systems by chemical doping. The realization of atmospheric superconductivity of Cr-based and Mn-based compounds is very important for the study of the unconventional superconductivity of CrAs and MnP. Based on this work, the doped CrAs and MnP0.8B0.2 single crystal samples were successfully prepared by flux method for the first time in this paper. The low temperature physical properties of CrAs1-xPx and MnP0.8B0.2 single crystal samples were studied systematically. In the first part, the basic physical properties of CrAs single crystal and the superconductivity of CrAs at high pressure are introduced, and then the CrAs1-xPx single crystal is reported for the first time. Experimental data on resistivity and specific heat of samples. Behavior of electrical resistivity and electron specific heat coefficient 緯 in normal state at low temperature. It is shown that there is a quantum critical point near the critical doping amount x0. 05. At this time, the long range magnetic order of CrAs has been completely suppressed. This is similar to the behavior of CrAs at high pressure. However, no superconductivity has been observed above 2K. In the second part, the superconductivity of MnP induced by high pressure is first introduced. Then MnP0.8B0.2 is reported for the first time. Resistivity of single crystal sample, The specific heat and magnetic susceptibility data. Mn0.8B0.2 single crystal sample has very small magnetic moment, The magnetoresistive effect of MnP0.8B0.2 is very strong at low temperature. The resistivity of MnP0.8B0.2 in the tilted antiferromagnetic state or spiral magnetically ordered state. MNP 0.8B 0.2 is very similar to the behavior of MnP pressurized 4-6GPa at low temperature. Debye temperature is basically the same as MnP, The density of states is much higher than that of MnP. The third part summarizes the work done at present and puts forward the unsolved problems and the future feasibility research direction.
【學位授予單位】：陜西師范大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TM26

【共引文獻】

相關期刊論文 前10條

1 路慶鳳,劉英豪,程國生;YBa_2Cu_3O_(6+x)光電導效應的研究進展[J];河南師范大學學報(自然科學版);2002年02期

2 李曉薇,董正超;三維態(tài)密度Van Hove奇點與高溫超導體的能隙[J];淮陰師范學院學報(自然科學版);2002年02期

3 黃有興,許祝安,沈靜琴,馮春木;高溫超導體中的能斯特效應與類渦旋激發(fā)[J];浙江大學學報(理學版);2004年01期

4 許祝安;朱增偉;沈靜琴;;高溫超導體中超導位相漲落:Nernst效應研究[J];科技導報;2005年12期

5 曹海濱;控溫與加壓對超導電性的影響[J];零陵學院學報;2004年05期

6 任清褒;高溫超導體正常態(tài)的輸運性質[J];麗水師范�？茖W校學報;2001年02期

7 廖楊芳;;高溫超導體中的自旋調制條紋相研究[J];貴州師范大學學報(自然科學版);2012年02期

8 曹天德,羅自樹;正常金屬與非費米液體間的隧穿[J];南昌航空工業(yè)學院學報;2000年03期

9 岳小萍;;統計性超導電子對密度與溫度無關[J];新鄉(xiāng)學院學報(自然科學版);2011年01期

10 路洪艷;劉強春;劉保通;;《高溫超導材料》課程體系建設與教學實踐探索[J];吉林師范大學學報(自然科學版);2010年04期

，

本文編號：1670598