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Structural effects of hydrostatic pressure in orthorhombic La[sub 2[minus][ital x]]Sr[sub [ital x]]CuO[sub 4]

Journal Article · · Physical Review, B: Condensed Matter; (United States)
 [1]; ; ; ; ; ;  [2]
  1. Institute for Solid State Physics, University of Tokyo, 7-22-1 Roppongi, Tokyo 106 (Japan)
  2. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

We have investigated the effect of hydrostatic pressure on the structure of orthorhombic La[sub 2[minus][ital x]]Sr[sub [ital x]]CuO[sub 4] between 1 atm and 0.6 GPa, using neutron powder diffraction. Increasing pressure causes the tilt angle of CuO[sub 6] octahedra to decrease, leading to a transition to tetragonal symmetry. There is a strong compressibility anisotropy for the orthorhombic structure. Order parameters for the transition versus pressure are consistent with Landau theory for a second-order transition. It is shown that this transition can be universally scaled over ([ital x],[ital T],[ital P]) space in the context of Landau theory. We conclude that [ital T][sub [ital c]] varies inversely with the tilt angle and is maximum for the tetragonal structure, i.e., for flat and square CuO[sub 2] planes, for this compound.

DOE Contract Number:
W-31109-ENG-38
OSTI ID:
7174818
Journal Information:
Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 50:5; ISSN PRBMDO; ISSN 0163-1829
Country of Publication:
United States
Language:
English