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arXiv · 0810.0287

Pressure effects on the electron-doped high Tc superconductor BaFe(2-x)Co(x)As(2)

K. Ahilan·J. Balasubramaniam·F. L. Ning·T. Imai·A. S. Sefat·R. Jin·M. A. McGuire·B. C. Sales·D. Mandrus
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Abstract

Application of pressures or electron-doping through Co substitution into Fe sites transforms the itinerant antiferromagnet BaFe(2)As(2) into a superconductor with the Tc exceeding 20K. We carried out systematic transport measurements of BaFe(2-x)Co(x)As(2) superconductors in pressures up to 2.5GPa, and elucidate the interplay between the effects of electron-doping and pressures. For the underdoped sample with nominal composition x = 0.08, application of pressure strongly suppresses a magnetic instability while enhancing Tc by nearly a factor of two from 11K to 21K. In contrast, the optimally doped x=0.20 sample shows very little enhancement of Tc=22K under applied pressure. Our results strongly suggest that the proximity to a magnetic instability is the key to the mechanism of superconductivity in iron-pnictides.

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K. Ahilan, J. Balasubramaniam, F. L. Ning, T. Imai, A. S. Sefat, R. Jin, M. A. McGuire, B. C. Sales, D. Mandrus. 2008-10-01. Pressure effects on the electron-doped high Tc superconductor BaFe(2-x)Co(x)As(2). https://doi.org/10.1088/0953-8984%2F20%2F47%2F472201

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