arXiv subjects

A. I. Ponomarev

Publications and source records attributed to A. I. Ponomarev.

3 recordsLinked to original sources

arXiv2002

The interplay of superconductivity and localization in Nd{2-x}Ce{x}CuO{4+δ} single crystal films

The influence of nonstoichiometric disorder on the in-plane resistivity and SC-transition has been investigated for Nd{2-x}Ce{x}CuO{4+δ} single crystal films (x=0.15 and 0.18). It is shown that with increasing of $δ$ the in-plane normal state resistivity increases (the mean free path diminishes) and SC-transition temperature decreases with essential broadening of the transition region. The observed evolution from homogeneous metallic (and superconducting) Nd{2-x}Ce{x}CuO{4+δ} system to inhomogeneous dielectric one is described as Anderson-type disorder-induced transition in a two-dimensional electron system.

cond-mat.supr-con↗

arXiv1999

Two-dimensional weak localization effects in high temperature superconductor Nd{2-x}Ce{x}CuO{4-d}

A systematic study of the resistivity and Hall effect in single crystal Nd{2-x}Ce{x}CuO{4-d} films (0.12 < x < 0.20) is presented, with special emphasis on the low-temperature dependence of the normal state conductance. Two-dimensional weak localization effects are found both in a normally conducting underdoped sample (x = 0.12) and in situ superconducting optimally doped (x = 0.15) or overdoped (x = 0.18) samples in a high magnetic field B > B{c2}. The phase coherence time and the effective thickness of a CuO{2} conducting layer {d} (~ 1.5 A) have been estimated by fitting 2D weak localization theory expressions to the magnetoresistivity data for magnetic fields perpendicular to the {ab} plane and in plane. Estimates of the parameter {d} ensure the condition of strong carrier confinement and justify a model consisting of almost decoupled 2D metallic sheets for the Nd{2-x}Ce{x}CuO{4-d} single crystal.

cond-mat.supr-con↗

arXiv1999

Two-dimensional quantum interference contributions to the magnetoresistance of Nd{2-x}Ce{x}CuO{4-d} single crystals

The 2D weak localization effects at low temperatures T = (0.2-4.2)K have been investigated in nonsuperconducting sample Nd{1.88}Ce{0.12}CuO{4-d} and in the normal state of the superconducting sample Nd{1.82}Ce{0.18}CuO{4-d} for B>B_c2. The phase coherence time and the effective thickness $d$ of a conducting CuO_2 layer have been estimated by the fitting of 2D weak localization theory expressions to the magnetoresistivity data for the normal to plane and the in-plane magnetic fields.

cond-mat.supr-con↗