Thermodynamic properties of excess-oxygen-doped La2CuO4.11 near a simultaneous transition to superconductivity and long-range magnetic order

Abstract

We have measured the specific heat and magnetization {\it versus} temperature in a single crystal sample of superconducting La${}_2$CuO${}_{4.11}$ and in a sample of the same material after removing the excess oxygen, in magnetic fields up to 15 T. Using the deoxygenated sample to subtract the phonon contribution, we find a broad peak in the specific heat, centered at 50 K. This excess specific heat is attributed to fluctuations of the Cu spins possibly enhanced by an interplay with the charge degrees of freedom, and appears to be independent of magnetic field, up to 15 T. Near the superconducting transition $T_c$($H$=0)= 43 K, we find a sharp feature that is strongly suppressed when the magnetic field is applied parallel to the crystallographic c-axis. A model for 3D vortex fluctuations is used to scale magnetization measured at several magnetic fields. When the magnetic field is applied perpendicular to the c-axis, the only observed effect is a slight shift in the superconducting transition temperature.

8 pages, 8 figures

References in corpus (7)

• Antiferromagnetic Order Induced by an Applied Magnetic Field in a High-Temperature Superconductor
• Order and quantum phase transitions in the cuprate superconductors
• Neutron Scattering Study of Spin Density Wave Order in the Superconducting State of Excess-Oxygen-Doped La2CuO4+y
• Muon spin relaxation studies of incommensurate magnetism and superconductivity in stage-4 La${}_2$CuO${}_{4.11}$ and La${}_{1.88}$Sr${}_{0.12}$CuO${}_4$
• Enhancement of long-range magnetic order by magnetic field in superconducting La2CuO(4+y)
• Neutron scattering study of the effects of dopant disorder on the superconductivity and magnetic order in stage-4 La_2CuO_{4+y}
• Vortex fluctuations in superconducting La-Sr-Cu-O

Cited by in corpus (2)

• Electron-Phonon-Driven Three-Dimensional Metallicity in an Insulating Cuprate
• ${}^{139}$La and ${}^{63}$Cu NMR investigation of charge order in La${}_2$CuO${}_{4+y}$ ($T_c=42$K)