Unconventional lattice stiffening in superconducting La2-xSrxCuO4 single crystals.
Unconventional lattice stiffening in superconducting La2-xSrxCuO4 single crystals.
复制标题
超导 La2-xSrxCuO4 单晶中的非常规晶格硬化。
DOI：
10.1103/physrevb.52.570
复制
发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Kojima
中科院分区：
文献类型：
--
作者：
Nohara;Suzuki;Maeno;Fujita;Tanaka;Kojima
Ultrasonic and specific-heat measurements have been performed on single crystals of ${\mathrm{La}}_{2\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Sr}}_{\mathit{x}}$${\mathrm{CuO}}_{4}$ (LSCO) with x=0.09, 0.14, and 0.19 across the superconducting transition temperature ${\mathit{T}}_{\mathit{c}}$. We observed jumplike decreases in the longitudinal elastic moduli at ${\mathit{T}}_{\mathit{c}}$, as are seen in conventional superconductors. Anisotropic strain dependence of ${\mathit{T}}_{\mathit{c}}$ was estimated from both the jump in the elastic moduli and specific heat at ${\mathit{T}}_{\mathit{c}}$ via the Ehrenfest relation. With further lowering temperature below ${\mathit{T}}_{\mathit{c}}$, we found a pronounced lattice stiffening in the elastic moduli of LSCO, which contrasts with the continuous softening observed in most of the conventional superconductors. Thermodynamic analysis revealed that the stiffening originates from the change in the superconducting condensation energy under the lattice strain. This unusual lattice stiffening in the superconducting state is possibly a common character of the high-${\mathit{T}}_{\mathit{c}}$ copper oxides.
Ultrasonic and specific-heat measurements have been performed on single crystals of ${\mathrm{La}}_{2\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Sr}}_{\mathit{x}}$${\mathrm{CuO}}_{4}$ (LSCO) with x=0.09, 0.14, and 0.19 across the superconducting transition temperature ${\mathit{T}}_{\mathit{c}}$. We observed jumplike decreases in the longitudinal elastic moduli at ${\mathit{T}}_{\mathit{c}}$, as are seen in conventional superconductors. Anisotropic strain dependence of ${\mathit{T}}_{\mathit{c}}$ was estimated from both the jump in the elastic moduli and specific heat at ${\mathit{T}}_{\mathit{c}}$ via the Ehrenfest relation. With further lowering temperature below ${\mathit{T}}_{\mathit{c}}$, we found a pronounced lattice stiffening in the elastic moduli of LSCO, which contrasts with the continuous softening observed in most of the conventional superconductors. Thermodynamic analysis revealed that the stiffening originates from the change in the superconducting condensation energy under the lattice strain. This unusual lattice stiffening in the superconducting state is possibly a common character of the high-${\mathit{T}}_{\mathit{c}}$ copper oxides.