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Second-phase segregation and micro strain/lattice parameter dependent transition temperature in polycrystalline MgB2

Journal Article


Abstract


  • Un-doped, metal-doped, and carbon-doped MgB2 samples were prepared by furnace cooling and quenching to investigate the second phase behavior and the resultant critical current density J c performance under different heat treatment processes, which is infrequently mentioned, and to explore the strain/lattice parameter dependence of the superconducting transition temperature. To release the residual stress, quenching induced second-phase segregation in these MgB2 samples shows a negative effect on the J c. Nevertheless, the dislocations and the lattice distortion assisted the enhancement of the high-field J c in the un-doped and metal-doped MgB2 samples, which indicated that quenching could be technically applied for the fabrication of metal-sheathed MgB2 wires and tapes to obtain excellent J c. After evaluating the micro strain and the lattice parameters' (c and a for hexagonal lattice) variation, a dome was observed in the illustration of the strain/lattice parameter c/a dependence of T c, which differed from the reported linear relation in previous work. This suggests that the c/a ratio and the strain may be the predominant parameters for scaling of the superconducting dome width in the superconducting phase diagram of MgB2.

Publication Date


  • 2016

Citation


  • Cai, Q., Liu, Y., Guo, Q., Ma, Z., & Li, H. (2016). Second-phase segregation and micro strain/lattice parameter dependent transition temperature in polycrystalline MgB2. Superconductor Science and Technology, 29(10). doi:10.1088/0953-2048/29/10/105013

Scopus Eid


  • 2-s2.0-84989851405

Web Of Science Accession Number


Volume


  • 29

Issue


  • 10

Place Of Publication


Abstract


  • Un-doped, metal-doped, and carbon-doped MgB2 samples were prepared by furnace cooling and quenching to investigate the second phase behavior and the resultant critical current density J c performance under different heat treatment processes, which is infrequently mentioned, and to explore the strain/lattice parameter dependence of the superconducting transition temperature. To release the residual stress, quenching induced second-phase segregation in these MgB2 samples shows a negative effect on the J c. Nevertheless, the dislocations and the lattice distortion assisted the enhancement of the high-field J c in the un-doped and metal-doped MgB2 samples, which indicated that quenching could be technically applied for the fabrication of metal-sheathed MgB2 wires and tapes to obtain excellent J c. After evaluating the micro strain and the lattice parameters' (c and a for hexagonal lattice) variation, a dome was observed in the illustration of the strain/lattice parameter c/a dependence of T c, which differed from the reported linear relation in previous work. This suggests that the c/a ratio and the strain may be the predominant parameters for scaling of the superconducting dome width in the superconducting phase diagram of MgB2.

Publication Date


  • 2016

Citation


  • Cai, Q., Liu, Y., Guo, Q., Ma, Z., & Li, H. (2016). Second-phase segregation and micro strain/lattice parameter dependent transition temperature in polycrystalline MgB2. Superconductor Science and Technology, 29(10). doi:10.1088/0953-2048/29/10/105013

Scopus Eid


  • 2-s2.0-84989851405

Web Of Science Accession Number


Volume


  • 29

Issue


  • 10

Place Of Publication