我们用传统的固相反应法烧结了一系列Mg1-xZnxB2(x=0.00,0.02,0.04,0.06,和0.08),仔细研究超导转变温度和结构,发现随着Zn掺杂量的增加,002峰向衍射角减小的方向转移,这使Zn原位替代Mg和晶格常数a的增大成为可能.电阻系数测量表明,被Zn替代后开始的超导转变温度(Tc)几乎没有变化,尤其,当掺杂量x不高于0.04时MgB2的Tc值只是轻微的增加.例如,没有掺杂的块体的Tc是38.5K,而x=0.02时为39K,x=0.04为38.7K.
A series of polycrystalline samples of Mg1-xZnxB2(x = 0.00,0.02,0.04,0.06,and 0.08) were fabricated by a conventional solid-state reaction method.The structure and superconducting transition temperature of the Zn-doping were investigated carefully.It is found that the position of(002) peaks shift towards smaller angles with Zn doping,which shows the possibility of Zn-substitution in the Mg-sites and extension of a-axis.The resistivity measurements indicated that the onset superconducting transition temperatures(Tc) are nearly unchanged by Zn-substitution,especially,Tc values of MgB2 were enhanced slightly when the doping level x is not higher than 0.04.For example,Tc is 38.5 K for the undoped sample,but changes to 39 K for x=0.02,38.7 K for x=0.04.
参考文献
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