Spin transitions in La0.7 Ba0.3CoO3 thin films revealed by combining Raman spectroscopy and X-ray diffraction

Abstract

International audienceIn cobaltite, the spin states transitions of Co3þ/4þ ions govern the magnetic and electronic conductionproperties. These transitions are strain-sensitive and can be varied using external parameters, includingtemperature, hydrostatic pressure, or chemical stresses through ionic substitutions. In this work,using temperature dependent Raman spectroscopy and X-ray diffraction, the epitaxial strain effectson both structural and vibrational properties of La0.7 Ba0.3 CoO3 (LBCO) cobaltite thin films areinvestigated. All Raman active phonon modes as well as the structure are found to be stronglyaffected. Both Raman modes and lattice parameter evolutions show temperature changes correlatedwith magnetic and electronic transitions properties. Combining Raman spectroscopy and X-ray diffractionappears as a powerful approach to probe the spin transition in thin film cobaltite. Our resultsprovide insight into strong spin-charge-phonon coupling in LBCO thin film. This coupling manifestsas vibrational transition with temperature in the Raman spectra near the ferromagnetic spin orderedtransition at 220K

Electronic interactions between graphene and cobaltite thin film La0.7Sr0.3CoO3 and its magnetic consequences

“…After the transfer of the graphene monolayer, we note the appearance of four additional modes at 259, 521, 616, 659 and 690 cm -1 . The observation of new peaks in such cobaltite material proves an electronic interaction and a change in the electronic configuration of the Co ions [9,30,31], promoting the IS states in Co 3+ and/or Co 4+ , which in turn activate the Raman modes associated to the JT distortions [30].…”

“…The doping of graphene by holes or electrons may therefore be responsible for these shifts [29]. To check the possibility of charge-transfer between the graphene and LSCO film, we follow not only the shift in frequencies of the graphene Raman modes, but also the LSCO Raman modes that are sensitive to changes of the electronic configuration of the Co ions [9,30,31].…”

The fabrication of layer‐by‐layer mode LaCoO3 film by pulsed laser deposition

“…The research on the relationship between the strain and spin effect in magnetic‐electric thin films has been widely studied worldwide; the strain in the thin films could influence the magnetic property sharply and produce a profound impact on the potential applications. The magnetic‐electric materials owned profound applications such as energy transfer and the control of magnetic‐electric devices …”

“…The research on the relationship between the strain and spin effect in magnetic-electric thin films has been widely studied worldwide; [1][2][3][4][5][6] the strain in the thin films could influence the magnetic property sharply and produce a profound impact on the potential applications.…”