Study of Transforming and NontransformingV3Si up to 29 kbar

High Pressure Effects on Superconductivity

“…This result suggests that the T c of a transforming sample should still increase with pressure if p exceeds the critical value p c above which the structural instability is completely suppressed. Extending the experimental pressure range to 2.9 GPa Chu and Diatschenko could later confirm this prediction [40]. By comparing the pressure coefficients of T c of transforming as well as NT V 3 Si single crystals it was unambiguously shown that T c (p) of the transforming sample does not exhibit the maximum predicted by the soft-phonon model but it changes slope above p c and the pressure coefficient for p>p c was found to be very close to the value of the NT sample.…”

High pressure studies on Fe-pnictide superconductors

“…12 for holedoped (K x Sr 1-x )Fe 2 As 2 , was revealed [56]. The effects of hydrostatic pressure up to 2.5 GPa on the SDW and superconducting transitions have been investigated by Ahilan et al [57] for an underdoped (x=0.04) and an optimally doped (x=0.1) sample of Ba(Fe 1-x Co x ) 2 derived the uniaxial pressure coefficients of T c for compression along the a-and c-axes. The pressure coefficients are quite large and very anisotropic, dT c /dp a =3.1 K/GPa and dT c /dp c =-7.0 K/GPa, indicating that T c of Ba(Fe 1-x Co x ) 2 As 2 strongly depends on the c/a ratio, similar to other layered superconductors (for example: La 2-x Sr x CuO 4 [59]).…”

“…For example, there are more naturally nonsuperconducting elements that have been turned into superconductors through the application of pressure in the last half-century than naturally occurring elemental superconductors [1]. It was the high pressure experiments on the A15 compound system to examine the correlation between superconductivity and lattice instabilities in the late 1970's and early 1980's that gave us the confidence that superconductivity could take place at temperatures above 30's K [2], in contrast to the then theoretical prediction [3]. Again, it was the high pressure experiments on cuprates that demonstrated that indeed a superconducting transition temperature (T c ) could be achieved above 50's K and suggested that the cuprate system warranted further exploration for novel physics and higher T c, besides providing hints for the search for T c > 50's K [4].…”

Alteration of the Superconducting Properties of A15 Compounds and Elementary Composite Superconductors by Nonhydrostatic Elastic Strain

“…(6) and (7) . Let us examine the available experimental evidence on this point (which is summarized in Table I).…”