Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
J Phys Condens Matter. 2010 Jun 9;22(22):222203. doi: 10.1088/0953-8984/22/22/222203. Epub 2010 May 20.
We report the synthesis of (Ca₀.₃₃Na₀.₆₆)Fe₂As₂ showing a superconducting transition with T(c) above 33 K. Both dc magnetic susceptibility or specific heat measurements indicated the bulk superconductivity nature of the sample. We also have successfully grown single crystals of the (Ca₀.₃₃Na₀.₆₆)Fe₂As₂ superconductors. The single crystals exhibit sharp superconducting transitions with T(c) above 33 K. The effects of magnetic field on the superconducting transitions are studied, giving rise to high upper critical fields with H(c₂)(c)≈85 T and H(c₂)(ab)≈172 T, respectively. The anisotropy parameter was calculated to be around 2.
我们报告了（Ca₀.₃₃Na₀.₆₆）Fe₂As₂的合成，该化合物表现出超导转变，临界温度 T(c)高于 33 K。直流磁 susceptibility 或比热测量均表明样品具有体超导性质。我们还成功地生长了（Ca₀.₃₃Na₀.₆₆）Fe₂As₂超导单晶。单晶表现出临界温度 T(c)高于 33 K 的尖锐超导转变。研究了磁场对超导转变的影响，得到了高的上临界场，H(c₂)(c)≈85 T 和 H(c₂)(ab)≈172 T。计算出的各向异性参数约为 2。
