Spin–phonon coupling in HoCr_1 − xFe_xO₃ (x = 0 and 0.5) compounds

Abstract

We report on the temperature dependent Raman scattering studies of polycrystalline HoCr1 − xFexO3 (x = 0 and 0.5) compounds. No signature of phonon mode related to structural phase transition is evident in the investigated temperature range in both the compounds. The thermal evolution of phonon spectra indicates a deviation of B3g(3) mode from the expected anharmonic behaviour below magnetic ordering temperature TN in HoCrO3 compound. This behaviour is attributed to spin–phonon coupling, which is due to the modulation of super exchange integral by lattice vibration. On the other hand, the anomalous behaviour of Ag mode and its line‐width around magnetic ordering in HoCr0.5Fe0.5O3 compound suggest the spin–phonon coupling. Apart from that, a clear deviation of wavenumber pertinent to B2g(1) mode suggests the possibility to observe ferroelectricity in HoCr0.5Fe0.5O3 compound. We believe that the present results would be helpful in obtaining new materials with multiferroicity near room temperature.

Magnetocaloric effect and spin-phonon correlations in RFe0.5Cr0.5O3 (R = Er and Yb) compounds

“…The changes in phonon lifetime also suggest the presence of disorder in the compounds due to magnetic order. This type of disorder can be influenced near magnetic ordering due to titling or rotation of octahedral, ordering of Fe/Cr ions in oxygen octahedral or due to displacement of the rare-earth ion [46]. Additionally, from Figs.…”

X-ray absorption near-edge, terahertz and Raman spectroscopies evidence growth-orientation dependent cation order, phase transitions and spin–phonon coupling in half-metallic Ca2FeMoO6 thin films

“…The value of ∆ω 0 is 79 cm −1 and 44 cm −1 for (111) and (100) oriented CFMO films, respectively (table 4). Literature reports suggest that the higher value of ∆ω 0 implies higher spin-phonon coupling strength in the system [33]. Thus, the temperature-dependent Raman data suggest that the CFMO (111) films with higher cation ordering exhibit stronger spin-phonon coupling with higher ∆ω 0 .…”

“…The temperature-induced thermal expansion of the lattice produces red-shift of the Raman modes as expected. For a magnetic material, the red-shift of Raman modes can be attributed to various factors such as [24,32,33]: ω (T) = ω 0 + ∆ω ph−ph + ∆ω sp−ph + ∆ω anharmonic (7) where ω 0 is the Raman shift corresponding to 0 K, ∆ω ph-ph is the cell volume contribution, ∆ω sp-ph is the spin-phonon coupling contribution and ∆ω anharmonic signifies the contribution of anharmonic terms in the system. Here, ∆ω sp-ph arises because of modulation of spin exchange integral by a change in the lattice vibrational frequencies and hence signifies contribution from spin-phonon interactions.…”

Recent advances in linear and nonlinear Raman spectroscopy. Part XIII

“…[161] Kotnana investigated spin-phonon coupling in HoCr 1−x Fe x O 3 (x = 0 and 0.5) compounds. [162] Koyanagi and coworkers reported a correlation among Raman spectra, swelling, and irradiation temperature in the Raman spectra of neutron irradiated silicon carbide. [163] Premila et al performed Raman spectroscopic studies across the ferroelectric transition in cobalt substituted dimethyl amine manganese formate.…”

“…They found that a numerous assemblage of organic inclusions is a diagnostic feature for gem quality green apatite from Anemzi . Kotnana investigated spin–phonon coupling in HoCr 1−x Fe x O 3 (x = 0 and 0.5) compounds . Koyanagi and co‐workers reported a correlation among Raman spectra, swelling, and irradiation temperature in the Raman spectra of neutron irradiated silicon carbide .…”