Journal ArticleDOI
Resistivity of nonmetallic La2-ySryCu1-xLixO4- delta single crystals and ceramics.
Marc Kastner,Robert J. Birgeneau,Changchen Chen,Yet-Ming Chiang,D. R. Gabbe,Hans P. Jenssen,T. Junk,C. J. Peters,P. J. Picone,Tineke Thio,T. R. Thurston,Harry L. Tuller +11 more
TLDR
The resistivity of nonmetallic La/sub 2-sub y/Sr/sub y,Cu/sub 1-//sub x/Li/sub X/O/sub 4-sub delta/ single crystals and ceramics accurately follows the functional form exp((T/sub 0/T)/sup 1/4/), characteristic of variable-range hopping as mentioned in this paper.Abstract:
The resistivity of nonmetallic La/sub 2-//sub y/Sr/sub y/Cu/sub 1-//sub x/Li/sub x/O/sub 4-//sub delta/ single crystals and ceramics accurately follows the functional form exp((T/sub 0//T)/sup 1/4/), characteristic of variable-range hopping. For each of the crystals grown from Li-containing flux and CuO flux, pure reduced ceramics, and ceramics containing 0.025 to 0.2 mol % Li, the values of T/sub 0/ are in the range 0.3--7 x 10/sup 6/ K. The hopping conductivity shows that the crystals, which also manifest the two-dimensional quantum spin fluid state, antiferromagnetism, and the tetragonal-to-orthorhombic transition, are nonmetallic because the electronic states at the Fermi energy are localized. No evidence of a large gap is observed, and all samples, including the reduced ceramic, are p type, leading to the suggestion that in the nonmetallic state as well as the superconductor, the Fermi energy lies near the top of the band of singly occupied states (lower Hubbard band). The suppression of superconductivity by Li impurities is discussed.read more
Citations
More filters
Journal ArticleDOI
The spin-polaron theory of high-Tc superconductivity
TL;DR: In this paper, a model for high-temperature superconductors which assumes that the carriers are holes in the (hybridized) oxygen 2p band and form "spin polarons" with the moments on the copper atoms is presented.
Journal ArticleDOI
Localized polarons and conductive charge carriers: Understanding CaCu 3 Ti 4 O 12 over a broad temperature range
TL;DR: In this paper, the combined effects of localized charge carriers (polarons) and conductive charge carriers using a recently proposed statistical model was used to fit and understand its permittivity measured at different frequencies over a broad temperature range.
Journal ArticleDOI
Spintronic Functionality of BiFeO3 Domain Walls
Ji Hye Lee,Ignasi Fina,Ignasi Fina,Xavi Marti,Xavi Marti,Young Heon Kim,Young Heon Kim,Dietrich Hesse,Marin Alexe,Marin Alexe +9 more
TL;DR: Anisotropic magnetoresistance at the BiFeO3 domain walls has been observed at the conductive domain walls of an insulating ferroelectric material, which implies that domain walls become an electrically tunable nanospintronic object.
Journal ArticleDOI
Superconductivity and localisation in the Bi2Sr2Ca1−xRExCu2O8+d(RE = Nd, Sm, Gd and Dy) system
TL;DR: In this paper, the effect of rare earth substitution on the structure, electrical conductivity, and hole concentration of Bi2Sr2CaCu2O8+d was investigated.
Journal ArticleDOI
Structural and electrical studies of mixed copper/ruthenium oxides and related compounds of zinc and antimony
TL;DR: In this article, the preparation and characterization of a number of mixed metal oxides of ruthenium and copper are described, the compounds being chosen to demonstrate the changes that occur on moving from the 3D perovskite structure to the 2-D K 2 NiF 4 structure via the intermediate Ruddlesden-Popper structure.