X-RAY-DIFFRACTION STUDY OF HGBA2CUO4-PRESSURES(DELTA AT HIGH)

An in situ high pressure study using energy dispersive X-ray diffracti on has been carried out on the polycrystalline high-T-c superconductor , HgBa2CuO4+delta (Hg-1201), to study its phase stability under pressu re and also to measure its compressibility and bulk modulus. No eviden ce of pressure-induced polymorphism was found in the pressure range in vestigated, i.e., from 0.1 MPa (1 atm) to 5 GPa. The compound exhibite d anisotropic elastic properties. The axial compressibility along the c axis was measured to be (3.96 +/- 0.35) x 10(-3) GPa(-1) and along t he a axis (3.42 +/- 0.13) x 10(-3) GPa(-1), corresponding to an anisot ropy ratio of 1.16 +/- 0.11. The bulk modulus was determined to be (94 .7 +/- 4.2) GPa and, assuming a Poisson's ratio of 0.2, Young's modulu s was estimated to be (170 +/- 8) GPa. (C) 1997 International Centre f or Diffraction Data.