Volume 100, Number 4, November 2012
|Number of page(s)||5|
|Section||Condensed Matter: Structural, Mechanical and Thermal Properties|
|Published online||04 December 2012|
P-T phase diagram of iron arsenide superconductor NdFeAsO0.88F0.12
1 Geophysical Laboratory, Carnegie Institution of Washington - 5251 Broad Branch Road NW, Washington DC 20015, USA
2 Institute of Crystallography, Russian Academy of Sciences - Leninsky pr. 59, Moscow 119333, Russia
3 Institute for Nuclear Research, Russian Academy of Sciences - Troitsk, Moscow 142190, Russia
4 L.V. Kirensky Institute of Physics, Siberian Branch of Russian Academy of Sciences - Krasnoyarsk 660036, Russia
5 Siberian Federal University - 79 Svobodny Prospect, Krasnoyarsk 660041, Russia
6 Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin Austin TX 78712-0254, USA
7 Beijing National Lab for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences P. O. Box 603, Beijing 100190, China
Received: 20 August 2012
Accepted: 6 November 2012
NdFeAsO0.88F0.12 belongs to the recently discovered family of high-TC iron-based superconductors. We have studied the influence of high pressure on transport properties of this material at low temperatures using the four-probe electrical conductivity technique in a diamond cell. Contrary to La-based compounds, we did not observe a maximum in TC under pressure. Under compression, TC drops rapidly as a linear function of pressure with the slope k = −2.8 ± 0.1 K/GPa. Under decompression, the behavior is completely reversible. The extrapolated value of TC at zero pressure is about TC (0) = 51.7 ± 0.4 K. At pressures higher than ∼18.4 GPa, the superconducting state disappears at all measured temperatures, although electrical resistance changes slope dramatically and shows a concave behavior. These observations may be related to the Kondo effect or to a weak localization of two-dimensional carriers at high pressures and low temperatures below ∼45 K, indicating a competition mechanism with the superconducting phase. On the bases of our experimental data, we propose a tentative P-T phase diagram of NdFeAsO0.88F0.12.
PACS: 62.50.-p – High-pressure effects in solids and liquids / 07.35.+k – High-pressure apparatus; shock tubes; diamond anvil cells / 74.72.-h – Cuprate superconductors
© EPLA, 2012
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