2006/03/01 by Kazuhiko Ikeuchi, Kazuyuki Isawa, Kazuyoshi Yamada +4 · 13 citations
Chemistry · Materials Science · Physics and Astronomy · #Analytical Chemistry (journal) #Chemistry #Condensed matter physics #Crystal (programming language) #Crystal growth #Crystallography #Diamagnetism #Diffraction #Doping #Lattice constant #Magnetic and transport properties of perovskites and related materials #Magnetic field #Magnetic properties of thin films #Materials science #Optics #Phase (matter) #Phase boundary #Phase diagram #Physics #Physics of Superconductivity and Magnetism #Single crystal #Superconductivity
paper · doi:10.1143/jjap.45.1594
published in Japanese Journal of Applied Physics 45(3R), 1594 (Institute of Physics)
openalex publication_date 2006/03/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We succeeded in growing sizable single crystals of La 2- x Sr x CuO 4 (LSCO) having a gradient in the Sr concentration along the axis of crystal growth. These crystals were completely characterized and the gradient of x ( x ∼0.03/cm), extending from x = 0.00 to 0.30, was determined from the positional dependences of local lattice constants and by inductively coupled plasma analysis. In accordance with the gradient of x , a gradient of hole concentration was also confirmed from the positional dependences of resistivity and superconducting transition temperatures. A real space boundary between the superconducting and the insulating phases was first observed as the boundary of the vortex state by scanning magnetic fields along the gradient of x using a scanning superconducting quantum interference device (SQUID) microscope. Precise measurement of the diamagnetic susceptibility of LSCO as a function of doping yielded a phase diagram that is consistent with one obtained from samples with constant x . We used these crystals for the phonon measurement with a synchrotron X-ray beam and succeeded in determining the doping dependence of the dispersion relation by changing the position of the incident beam spot on the crystals with the same experimental setup.