Study of phase coexistence in YVO₃ and LaVO₃

Abstract

The coexistence at low temperature in YVO 3 and LaVO 3 of two competing phases with defined orbital and spin orientations is studied by Raman spectroscopy. The temperature evolution of the phonons indicates that phase coexistence, due to strain in YVO 3 and fluctuations in LaVO 3 , is not restricted to small R ionic radius in RVO 3 compounds. Also, a typical temperature at 50 K is inferred from the temperature dependence of the intensities in LaVO 3 .

Probing orbital ordering in LaVO3 epitaxial films by Raman scattering

“…16,17,19 It originates from an out-of-phase oxygen stretching mode along the c-axis and has a B 1g symmetry in the orthorhombic Pbnm phase and a Ag symmetry in the monoclinic OO phase. 2,[16][17][18]32 This Raman mode was observed for LaVO 3 crystals for xx-polarized light and not for zz-polarized light (the relations of the optical axes, x, y, and z, to the orthorhombic axes a, b, c are x = a + b, y = a − b, and z = c). 2,16,17,19 We monitored this particular Raman peak in the spectra of a 55 nm thick LaVO 3 film grown on DSO(110) substrate.…”

“…Temperature-dependent Raman scattering and optical conductivity investigations of LaVO 3 single crystals were performed in great detail, in order to study the coupling between structure and electronic properties in the SO and OO states. 2,[16][17][18][19][20] Here we investigate the structural phase transitions and the onset of the orbital ordering in LaVO 3 epitaxial films fabricated by pulsed-laser deposition (PLD). Temperature-dependent Raman scattering spectroscopy was employed to monitor the occurrence of orbital ordering and its associated structural phase transition in LaVO 3 epitaxial films.…”

“…The Raman spectra of LaVO 3 show the activation of a characteristic band at 719 cm −1 (89 meV) below the OO transition. 2,[16][17][18]20 This band is readily observed using excitation resonant to the Mott-Hubbard gap near 2 eV, such as the light of a HeNe laser (1.96 eV). 16,17,19 It originates from an out-of-phase oxygen stretching mode along the c-axis and has a B 1g symmetry in the orthorhombic Pbnm phase and a Ag symmetry in the monoclinic OO phase.…”

“…Around 700 cm −1 (86 meV), a broad peak is visible already at RT which it splits into two peaks at 90 K, one at 701 cm −1 (86 meV) and one at 725 cm −1 (90 meV). The former was attributed to the phonon density of states 18 and the latter has been assigned to the A g out-of-phase oxygen stretching mode. For LaVO3/LGO(110), the mode is shifted to higher energy as compared to the mode in LaVO 3 /DSO(110) samples, in which it occurs at 717 cm −1 (89 meV) at 88 K. This energy difference indicates that compressive and tensile epitaxial strain influences the structure of LaVO 3 epitaxial films.…”

Recent advances in linear and non‐linear Raman spectroscopy. Part X

“…studied the phase coexistence in YVO 3 and LaVO 3 . The temperature evolution of the phonons indicates that phase coexistence, due to strain in YVO 3 and fluctuations in LaVO 3 , is not restricted to small R ionic radius in RVO 3 compounds …”