Structural transitions in a doped lanthanum cuprate

Abstract

139La NMR and relaxation measurements have been performed on La{1.8-x}Eu{0.2}Sr{x}CuO{4} (x = 0.13 and 0.2) single crystals. The temperature dependence of the 139La NMR spectra in all the structural phases (HTT -> LTO -> LTT) reveals the non-vanishing tilt angle of the CuO6 octahedra in the HTT phase, opposed to the case of La{2-x}Sr{x}CuO{4} where the tilt angle disappears immediately above the transition. Since 139La relaxation data provide evidence of the thermodynamic critical fluctuations associated with the structural phase transitions, HTT -> LTO and LTO -> LTT, we conclude that the structural transitions in Eu-doped La{2-x}Sr{x}CuO{4} should be of the order-disorder type rather than of the displacive type observed in La{2-x}Sr{x}CuO{4}. The change of the nature of the structural transitions caused by doping Eu appears to be consistent with the LTO -> LTT transition that is absent in La{2-x}Sr{x}CuO{4}.

5 pages, 4 figures, published in PRB

References in corpus (6)

• Lattice symmetry breaking in cuprate superconductors: Stripes, nematics, and superconductivity
• Phonon thermal conductivity in doped $\mathbf{L}{\mathbf{a}}_2\mathbf{Cu}{\mathbf{O}}_4$: Relevant scattering mechanisms
• Dzyaloshinsky-Moriya Spin Canting in the LTT Phase of La2-x-yEuySrxCuO4
• Incommensurate lattice distortion in the high temperature tetragonal phase of La${}_{2-x}$(Sr,Ba)${}_x$CuO${}_4$
• The Local Structure of La1.65Eu0.2Sr 0.15CuO4 determined by 63Cu NMR Spectroscopy and Van Vleck Paramagnetism of Eu3+ Ions
• ${}^{139}$La NMR investigation in underdoped La${}_{1.93}$Sr${}_{0.07}$CuO${}_4$

Cited by in corpus (5)

• Unconventional electronic order in a codoped high-Tc superconductor
• Magnetic field induced anisotropy of ${}^{139}\mathrm{La}$ spin-lattice relaxation rates in stripe ordered ${\mathrm{La}}_{1.875}{\mathrm{Ba}}_{0.125}{\mathrm{CuO}}_4$
• Cu nuclear magnetic resonance study of charge and spin stripe order in La${}_{1.875}$Ba${}_{0.125}$CuO${}_4$
• Coherent Charge and Spin Density Waves in Underdoped HgBa${}_2$CuO${}_{4+\delta }$
• Spin-stripe order tied to the pseudogap phase in La1.8-xEu0.2SrxCuO4