Exploratory Research On Light Element Superconducting Materials

This article first briefly introduces the origin of superconductivity and the development of superconducting materials,and then introduces several classic superconductors popular in recent years,such as copper-based and iron-based superconductors.Then introduced the three tasks during the master's degree.The first work is that we reported the use of microwave method to synthesize Mo_3-xRe_xAl₂C(0?x?0.3)superconductor and the physical properties of the doping effect.Re doping into Mo₃Al₂C will cause the lattice constant to decrease regularly,which is characterized by a linear decrease in the lattice parameter a from 6.868(1)(?)(for Mo₃Al₂C)to 6.846(2)(?)(for Mo_2.7Re_0.3Al₂C).After Re doping,the superconducting transition temperature T_c of Mo_3-xRe_xAl₂C first increases and then decreases.At the optimal doping level of x=0.09 with the maximum T_c=9.14 K.Our report provides a convenient method to synthesize Mo_3-xRe_xAl₂C in only a few minutes,and marks the first Re-doping study to enhance superconductivity on a non-centrosymmetric superconductor Mo₃Al₂C.The second work is in the topological semi-metal Mo₅Si₃,we conducted P doping research on it,and found that P doping induced strong coupling superconductivity in Mo₅Si₃.The optimal doping level is reached when P replaces half of the Si site,superconductivity of 10.7 K was induced in the non-superconducting topological semimetal Mo₅Si₃.Through the measurement of specific heat,we found that the superconductor ? is also increasing with the increase of P doping content,and ? is positively correlated with the Fermi surface density N(E_F).This may be due to the cost of electron doping introduced by P.Rice noodles have changed.P-doping increases N(E_F),thereby enhancing the electron-phonon coupling strength,and this turn induces superconductivity in the topological semimetal Mo₅Si₃.The third work is that we found the signs of superconductivity of 4.5 K in the alloy Hf VGe through the measurement of the magnetic susceptibility.But we still need to go further to determine its signs of superconductivity through the measurements of other physical properties such as electrical resistance and specific heat.In summary,we successfully synthesized Mo_3-xRe_xAl₂C(0?x?0.3)superconductor using microwave method,which also implies the first superconductivity enhancement doping study of non-centrosymmetric superconductor Mo₃Al₂C.And we induced a strong coupling superconductivity of 10.7 K through P doping in the topological semimetal Mo₅Si₃.We also found the superconductivity of 4.5 K in the Hf VGe alloy through the measurement of the magnetic susceptibility,but we still need to further determine its superconductivity through the measurement of resistance and specific heat.These works expand the research of Mo-based superconductor systems.At the same time provide some experience for related systems to study doping effects.