[7p-S42-1~16] 11.1 Fundamental properties

[7p-S42-5] Magnetic measurements and structural analyses of severely-strained Nb under pressure

〇Yuichirou Kitamura¹, Ryou Shiraishi¹, Kazuma Ogata¹, Masasi Tanaka¹, Masaki Mito¹, Takayuki Tajiri², Terukazu Nishizaki³, Kaveh Edalati⁴, Zenji Horita⁴ (1.Kyushu Inst. Tech, 2.Fukuoka Univ, 3.Kyushu Sangyo Univ, 4.Kyushu Univ)

Keywords:superconductivity, high-pressure torsion, hydrostatic pressure effects

Shear strain has been used as a negative factor to enhance superconductivity so far. We are trying to utilize this shear strain as a positive factor. In the present work, we have investigated the hydrostatic pressure effects on Nb which was subjected to severe plastic deformation. Indeed, this approach reduces the optimal pressure to stabilize the highest superconducting transition temperature Tc, and its Tc is over the previous record. At around the characteristic pressure, anisotropic structural change occurs, there is any correlation between structure and superconductivity.