我们通过固态反应法制备了MgxB2(x=0.2,0.6,0.8,1.0,1.2,1.4,1.8,2.2,2.6)系列超导样品.用四引线法测量了每一个样品在制备烧结过程中的高温R～T曲线.由这些曲线的升温阶段数据得知MgxB2系列样品的起始成相温度Tonset随着x值的增加而降低.由它们的X光衍射图可知,x≤1.0时,没有Mg和MgO的杂相峰;到x＞1.0后,随x值的增大,杂相Mg和MgO的衍射峰强度逐渐增强.它们的低温R～T曲线表明随x值的增加,正常态电阻减小,起始超导转变温度在39.3 K到39.9 K之间.综合Tc(onset)和△Tc,Mg1.4B2样品呈现出最好的超导状态.这些样品的单位质量M～T测量数据表明起起转变温度处于37.4～38.6 K之间,且Mg1.4B2样品呈现出最高的磁测Tc(onset)=38.60 K.在Mg含量x大于或低于1.4时,磁测Tc(onset)均小于此值.综合R～T和M～T这两种测量,为得到高Tc的MgB2超导块材,胚体MgB2的配比应取x=1.4为好.
参考文献
| [1] | J Nagamatsu;N Nakagawa;T Muranaka;Y.Zenitani J.Akimitsu .[J].Nature,2001,410:63. |
| [2] | S L Budko;G Lapertot;C Petrovic;C.E.Cunningham,N.Anderson,and P.C.Canfield .[J].Physical Review Letters,2001,86:1877. |
| [3] | P Bordet;M Mezouar;M Nú(n)ez-Regueiro;M.Monteverde,M.D.Nú(n)ez-Regueiro,N.Rogado,K.A.Regan,M.A.Hayward,T.He,S.M.Loureiro,and R.J.Cava .[J].Physical Review B,2001,64:172502. |
| [4] | P Szabó;P Samuely;J Ka(c)mar(c)ík;T.Klein,J.Marcus,D.Fruchart,S.Miraglia,C.Marcenat,and A.G.M.Jansen .[J].Physical Review Letters,2001,87:137005-137001. |
| [5] | F Bouquet;R A Fisher;N E Phillips;D.G.Hinks,and J.D.Jorgensen .[J].Physical Review Letters,2001,87:047001-047001. |
| [6] | D K Finnemore;J E Ostenson;S L Budko;G.Lapertot, P.C.Canfield .[J].Physical Review Letters,2001,86:2420. |
| [7] | V Braccini;A Gurevich;J E Giencke;M.C.Jewell,C.B.Eom,D.C.Larbalestier,A.Pogrebnyakov,Y.Cui,T.Liu,Y.F.Hu,J.M.Redwing,Q.Li,X.X.Xi,R.Singh,R.Gandikota,J.Kim,B.Wilkens,N.Newmann,J.Rowell,B.Moeckly,V.Ferrando,C.Tarantini,D.Marr,M.Putti,C.Ferdeghini,R.Vaglio,and E.Haanap .[J].Physical Review B,2005,71:012504. |
| [8] | X H Zeng;A V Pogrebnyakov;A Kotcharov;J.Ones,Jones,X.X.Xi,E.Lysczek,J.M.Redwing,S.Xu,Q.Li,J.Lettieri,D.G.Schlom,W.Tian,X.Pan,and Z.K.Liu.[J].Nature Materials,2002(01):35. |
| [9] | Yanwei Ma;Xianping Zhang;G Nishijima;K.Watanabe,and S.Awaji,Xuedong Bai .[J].Applied Physics Letters,2006,88:072502. |
| [10] | Chinping Chen;Kin-feng Wang;Ying Lü;Zhang Jia,Jing-pu Guo,Xiao-nan Wang,Meng Zhu,Xiang-yu Xu,Jun Xu,Qingrong Feng .[J].Physica C,2004,416:90-94. |
| [11] | Fen Li;Tao Guo;Kaicheng Zhang .Thick polycrystalline MgB_2 film on Cu substrate by hybrid physical-chemical vapour deposition[J].Superconductor Science & Technology,2006(11):1196-1199. |
| [12] | Chinping Chen;Qing-rong Feng;Zi-zhao Gan;Yu-fei Liu,Lingwen Kong,Lin Li,Zhang Jia,Jing-pu Guo,Cheng-gang Zhuang,Li-li Ding,Li-ping Chen,Fen Li,Kai-cheng Zhang,Ju Xu .[J].Chinese Science Bulletin,2005,50:719. |
| [13] | Y Feng;Y Zhao;A K Pradhan .Fabrication and superconducting properties of MgB_2 composite wires by the PIT method[J].Superconductor Science & Technology,2002(1):12-15. |
| [14] | Qing-rong Feng;Xun Chen;Yu-hao Wang;Xin Wang,Guangcheng Xiong,Zheng-xiang Gao .[J].Physica C,2003,386:653-656. |
| [15] | S C Yan;G Yan;C F Liu;Y.F.Lu,L.Zhou.Experimental study on the phase formation for the Mg-B system[J].Journal of Alloys and Compounds |
| [16] | Qing-rong Feng;Xin Wang;xin-jie Wang;Guang-cheng Xiong .[J].Solid-State Communications,2002,122:459-461. |
| [17] | Jun XuLing-wen Kong;Xin Chen;Yong-zhong Wang;Zheng-xiang Gao .[J].Physica C,2004,411:41-46. |
| [18] | Milton Ohring.Materials Science of Thin Films,Deposition and Structnre[M].ACADEMIC PRESS;Elsevier(Singapore) Pte Ltd,2006:97-100. |
上一张
下一张
上一张
下一张
计量
- 下载量()
- 访问量()
文章评分
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%