Phase diagram and phase separation in La2-x Srx CuO4+δ
Journal of Alloys and Compounds 207-208:C (1994) 206-212
Abstract:
The phase diagram of the title system is remarkably rich, exhibiting regions of long-range antiferromagnetic order, short-range (spin-glass-like) order, high temperature superconductivity, or none of these. Here, the phase diagram is reviewed, with an emphasis on our recent studies using 139La NQR, powder and single crystal neutron diffraction, and magnetization measurements for 0≤χ≤0.15 and 0≤δ≤0.1. © 1994.Phase separation and doped-hole segregation in La2 CuO4+δ and La2-x Srx CuO4+δ
Physica C: Superconductivity and its applications 235-240:PART 1 (1994) 257-260
Abstract:
Herein, we review the magnetic, superconducting and structural phase diagrams of the title systems, with an emphasis on our recent results form magnetic and structural neutron diffraction, magnetic susceptibility and system, and indicate the occurrence of frustrated phase separation on a nanoscopic length scale in the La2-xSrxCuO4 system with O < x ≲ 0.05. 139La nuclear quadrupole resonance measurements. The results clarify the miscibility gap in the La2CuO4+δ. © 1994.Suppression of superconductivity in orthorhombic La2-x Mx CuO4 (M=Ca,Sr)
Physica C: Superconductivity and its applications 235-240:PART 1 (1994) 339-340
Abstract:
We have extended the calcium solid-solubility limit in La2-xCaxCuO4 to x = 0.2 using synthesis at high oxygen pressure. The superconducting transition temperature increases with doping to 34 K at x = 0.15 and is suppressed for x > 0.15, similar to the Sr-substituted material. At a fixed doping level, the optimum superconducting properties (the highest Tc) are found for flat and square CuO2 planes. © 1994.Synthesis, crystal structure and properties of Hg2 Ba2 (Y, Ca) Cu2 O8-δ : the first cuprate superconductor containing a double mercury-oxygen layer
Physica C: Superconductivity and its applications 235-240:PART 2 (1994) 925-926
Abstract:
The first cuprate superconductor containing double (HgO)2 layers was synthesized using a high-pressure, high-temperature technique. The compound, with chemical formula Hg2Ba2Y1-xCaxCu2O 8-δ, contains a rock salt-type double HgO layer. The prototype compound Hg2Ba2YCu2O8-δ is an insulator. Superconductivity is induced in the system by partially replacing yttrium with calcium. © 1994.Tunnel junctions on 1:2:4 YBaCuO single crystal
Physica C: Superconductivity and its applications 235-240:PART 3 (1994) 1913-1914