Ultrasonic evidence of strong vibrational anharmonicity in high-Tcsuperconductors and its effect on determination of their elastic properties

Critical behavior ofLa0.75Sr0.25MnO3Kim1, Zink2, Hellman3 et al. 2002Phys. Rev. B1663810View full textAdd to dashboardCite

“…15͒ and bulk modulus of La 1.8 Sr 0.2 CuO 4 . 16,17 The most obvious feature in C P (T) is the -shaped peak located near 347 K associated with the phase transition. The sharpness of the peak indicates the uniformity and homoge-neity of this single-crystal sample.…”

Antiferromagnetism in a Cr86Ru14 alloy

“…8(a)-(e). γ L and γ S were then calculated using similar approaches applied [21] to the analysis of polycrystalline high-T c superconductors by treating the polycrystalline Cr 86 Ru 14 sample as an elastic isotropic medium. For an isotropic material the two independent elastic constants are given in terms of the Lamé constants, λ and μ, as the longitudinal elasticity constant c 11 = λ + 2μ = ρv 2 L and the shear elasticity constant c 44 = μ = ρv 2 S , where ρ is the density.…”

Ultrasonic determination of the elastic moduli and their pressure dependences in very dense YBa{sub 2}Cu{sub 3}O{sub 7{minus}x}

“…x [1][2][3] (and other related cuprates, including GdBa2Cu_OT.xin both its orthorhombic and tetragonal forms [4,5], Bi2Sr_Ca_tCu, O4+2,(with n=2 and 3) [6] and Lal.xSr0.2CuO4 [3]) is much smaller than that B r(p) determined [7][8][9][10][11][12] at very high pressures from x-ray measurements of lattice parameters in a diamond cell. This difference has been ascribed [1][2][3][4][5][6] to the large magnitude of (OB/OP)e--o determined from the effects of hydrostatic pressure on ultrasonic wave velocity.…”

“…x [1][2][3] (and other related cuprates, including GdBa2Cu_OT.xin both its orthorhombic and tetragonal forms [4,5], Bi2Sr_Ca_tCu, O4+2,(with n=2 and 3) [6] and Lal.xSr0.2CuO4 [3]) is much smaller than that B r(p) determined [7][8][9][10][11][12] at very high pressures from x-ray measurements of lattice parameters in a diamond cell. This difference has been ascribed [1][2][3][4][5][6] to the large magnitude of (OB/OP)e--o determined from the effects of hydrostatic pressure on ultrasonic wave velocity. A recent reanalysis [ 13] of the high pressure x-ray [7][8][9][10][11][12] and neutron [14][15][16] diffraction data has led to a substantial reduction of Br(p) and a large increase in the value of its pressure derivative (igB/OP): both trending towards the ultrasonic values and conf'm'rfing the earlier observation [1,2] of the highly pressure dependent nature of the bulk modulus at moderate pressures.…”