Preparation of Hg based superconducting wire by solution spinning method.

本文研究了溶液纺丝法制备Hg基超导线材的方法，采用Ba、Sr、Ca、Cu的醋酸盐、过氧化氢铵、聚乙烯醇和有机酸的混合溶液，通过干法纺丝制备了Hg基超导线材的前驱体。将直径为250 μ m的拉制原丝热解以除去挥发性组分，然后煅烧。在真空熔融石英中，灯丝与Hg_1（Ba，Sr）<0.1>_2Ca_1Cu_2Re_O_x或Hg_1（Ba，Sr）<0.2>_2Ca_2Cu_3Re_O_x颗粒反应。通过控制加热条件，加入Re，制备了单相Hg 1212（1）或Hg 1223（2）超导体。（1）和（2）的超导细丝的T_c分别为93 K和127 K，在77 K和0 T时的J_c分别为2300 A/cm ^2和1000 A/cm ^2<0.2>。在350 ℃以下的氧气流中进行退火，可提高试样的J_c。在77 K下，研究了F对Hg 1223灯丝输运J_c的影响. F的掺杂使Hg 1223灯丝形成了致密的液相线织构，并显著改善了J_c的场依赖性.通过控制加热条件和添加微量HgCl_2，在77 K和0 T下测得最大J_c值为10^4A/cm ^2。

We have studied the preparation of Hg based superconducting wire by solution spinning method.Long precursor filaments were prepared by dry spinning through a homogeneous aqueous solution mixed acetates of Ba, Sr, Ca and Cu, ammonium perrhenate, poly (vinyl alcohol) and organic acids. The as-drawn filament with a diameter of 250 mum was pyrolyzed to remove volatile components and then calcined. The filaments reacted in an evacuated fused quartz with a pellet of Hg_1 (Ba, Sr) _2Ca_1Cu_2Re_<0.1>O_x or Hg_1 (Ba, Sr) _2Ca_2Cu_3Re_<0.2>O_x. A single phase of filamentary Hg1212 (1) or Hg1223 (2) superconductor is prepared with Re addition by controlling the heating condition. The T_c of the (1) and (2) filaments is 93 K and 127 K and J_c at 77K and 0 T is 2300A/cm^2 and 1000A/cm^2, respectively.A superconducting F-doped Hg_xBa_2Cu_3Re_<0.2>O_y filament was examined to enhance the J_c by using a pellet containing BaF_2. The J_c of the specimens was enhanced by post-annealing up to 350ﾟC in O_2 flow. The influence of fluorine on the transport J_c of the F-doped Hg1223 filament at 77K was examined in magnetic fields of up to 10 T.F-doping resulted in a formation of dense liquidus texture and marked improvement in the field dependence of J_c for the filament. A J_c of more than 10^2A/cm^2 was maintained at 77 K in a field of 10 T.By controlling the heating condition and addition of a trace HgCl_2, a maximum J_c value of 10^4A/cm^2 at 77 K and 0 T was measured.