ACTA

Compression Changes in Electrical Resistance and Critical Temperature of Nb_1-xSe₂Sn_x Single Crystals

M.A. Obolenskiy^a, D.D. Balla, A.A. Zavgorodniy^a, R.V. Vovk^a, Z.F. Nazyrov^a, I.L. Goulatis^a, M. Januszczyk^b and J.N. Latosińska^b
^aV.N. Karazin Kharkiv National University, 4 Svoboda Sq., 61077 Kharkov, Ukraine
^bAdam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland

Received: May 20, 2011; in final form March 9, 2012

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In this work we investigate the influence of hydrostatic pressure (up to 12 kbar) on the critical parameters of Nb_1-xSe₂Sn_x (x=0.1 and x=0.15) single crystals. It is shown that a change in the density of states at the Fermi level brings the main contribution to the increase in T_c under pressure. Under the effect of hydrostatic pressure, the phonon spectrum is shifted to higher frequencies (narrowed). The estimated Debye temperature is consistent with those obtained from the heat capacity measurements in NbSe₂ single crystals. It is shown that upon increasing hydrostatic pressure the mean free path increases and Nb_1-xSe₂Sn_x should be considered as the pure limit in the Ginzburg-Landau theory.

DOI: 10.12693/APhysPolA.122.159
PACS numbers: 74.25.Fy, 74.62.Fj