相关论文: Excess oxygen in La_{2-x}Sr_xCoO_4

The relatively low Tc of Bi2Sr2CuO6+D allows to study normal-state down to low temperatures and the non-substituted compound is intrinsically strongly overdoped. Hole concentration can be adjusted trough oxygen excess, but few data exist in…

Oxygen nonstoichiometry, electrical conductivity and thermal expansion of La2 xSrxNiO4-\delta phases with high levels of strontium substitution (1 =< x =< 1.4) have been investigated in air and oxygen atmosphere in the temperature range…

The longstanding notion of stripe incommensurability being proportional to doping, \delta(x) ~ x, in lanthanum transition-metal oxides, La_{2-x}Sr_xTmO_4 (Tm = Cu, Ni, Co), is partly borne out by experiment but also plagued with exceptions.…

We present a detailed room temperature x-ray powder diffraction study on La2-xSrxNiO4+d with 0<=x<=0.12 and 0<=d<=0.13. For x=0.02, 0.04 and 0.06 the oxygen content phase diagrams of the Sr doped samples show a similar sequence of pure…

The dispersion of the Cu-O bond-stretching vibrations in overdoped La$_{1.7}$Sr$_{0.3}$CuO$_4$ (not superconducting) has been studied by high resolution inelastic neutron scattering. It was found that the doping-induced renormalization of…

We present local structural evidence for the existence of charge inhomogeneities at low temperature in underdoped and optimally doped La_2-xSr_xCuO_4. The inhomogeneities disappear for x > 0.2. The evidence for the charge inhomogeneities…

The oxygen isotope effect on the superconductivity, stripe phase and structure transition is systematically investigated in La$_{1.6-x}$Nd$_{0.4}$Sr$_{x}$CuO$_4$ with static stripe phase. Substitution of $^{16}$O by $^{18}$O leads to a…

Stripe order in La{2-x}Sr{x}NiO4 beyond x = 1/3 was studied with neutron scattering technique. At low temperatures, all the samples exhibit hole stripe order. Incommensurability \epsilon of the stripe order is approximately linear in the…

Short-range lattice superstructures have been studied with high-energy x-ray diffuse scattering in underdoped, optimally doped, and overdoped $\rm (Y,Ca)Ba_2 Cu_3 O_{6+x}$. A new four-unit-cell superstructure was observed in compounds with…

We analyze the results of point-contact measurements in La_{2-x}Sr_{x}CuO_{4} (LSCO) previously reported as a clear evidence of the separation between gap and pseudogap in this copper oxide. Here we show that, in addition to this, the…

La$_2$NiO$_{4+\delta}$ has attracted increasing interest in recent years, both as oxygen electrode in solid oxide fuel cells and electrolysers due to its high electrochemical activity at intermediate to high temperatures, and as key…

Inelastic light-scattering spectra of underdoped ${\rm La_{2-x}Sr_xCuO_4}$ (LSCO) single crystals are presented which provide direct evidence of the formation of quasi one-dimensional charged structures in the two-dimensional $\rm CuO_2$…

The anelastic spectrum of La{2-x}Sr{x}CuO{4} (x = 0, 0.008, 0.019, 0.032) has been measured down to 1.5 K, in order to see the effect of doping on the intrinsic lattice fluctuations already found in stoichiometric La{2}CuO{4}, and…

Charge-order stripes of different types occur when copper oxides are doped with either heterovalent metal, like $La_{2-x}Sr_xCuO_4$, or oxygen, like $YBa_2Cu_3O_{6+y}$. The difference shows up in the doping dependence of their…

A neutron scattering study of nonsuperconducting La$_{2-x}$Sr$_x$CaCu$_2$O$_6$ (x=0 and 0.2), a bilayer copper oxide without CuO chains, has revealed an unexpected tetragonal-to-orthorhombic transition with a doping dependent transition…

A high temperature electrochemical oxidation process has been used to produce large single crystals of $La_2CuO_{4 + \delta}$ suitable for neutron scattering experiments. Below room temperature the oxygen-rich phases have structural…

We have grown a single crystal of La_2-x_Sr_x_CuO_4_ in which the Sr concentration, x, continuously changes from 0.24 to 0.29 in the overdoped regime and obtained many pieces of single crystals with different x values by slicing the single…

The in-plane resistivity of the high-temperature oxide superconductor La$_{2-x}$Sr$_{x}$CuO$_{4}$ [LSCO] shows a strong growth of a contribution linear in temperature as the doping is reduced in the overdoped region toward optimal. This…

The evolution from superconducting LiTi2O4-delta to insulating Li4Ti5O12 thin films has been studied by precisely adjusting the oxygen pressure during the sample fabrication process. In the superconducting LiTi2O4-delta films, with the…

Purely local experimental probes of many copper oxide superconductors show that their electronic states are inhomogeneous in real space. For example, scanning tunneling spectroscopic (STS) imaging shows strong variations in real space, and…