Magnetic measurements of superconducting LiFeAs single crystals under high pressure.

Measurements of DC magnetization for single crystal specimens of LiFeAs have been performed under pressure using liquid argon and NaCl as pressure transmitting media (PTM) to generate hydrostatic and nearly uniaxial pressure along c -axis, respectively. It has been found that T c linearly decreases under pressure with pressure coefficient dT c / dP ∼ − 1.6 − 1.7 K/GPa, and then shows a pressure independent behavior with T c ∼ 8 K above 5 GPa. These behaviors are observed independently of whether we select liquid argon or NaCl as PTM. This suggests that c -axis lattice constant is not an important factor to determine T c in LiFeAs, in contrast to K x Fe 2 − y Se 2 and ( NH 3 ) y A x Fe 2 Se 2 (A=alkali metal). [ABSTRACT FROM AUTHOR]