Imaging oxygen defects and their motion at a manganite surface

Abstract

manganites are technologically important materials, used widely as solid oxide fuel cell cathodes; they have also been shown to exhibit electroresistance. oxygen bulk diffusion and surface exchange processes are critical for catalytic action, and numerous studies of manganites have linked electroresistance to electrochemical oxygen migration. Direct imaging of individual oxygen defects is needed to underpin understanding of these important processes. Currently, it is not possible to collect the required images in bulk, but scanning tunnelling microscopy (sTm) could provide such data for surfaces. Here, we report the first atomic resolution images of oxygen defects at a manganite surface. our experiments also reveal defect dynamics, including oxygen adatom migration, vacancy-adatom recombination and adatom bistability. Beyond providing an experimental basis for testing models describing the microscopics of oxygen migration at transition-metal oxide interfaces, our work resolves the long-standing puzzle of why sTm is more challenging for layered manganites than for cuprates.

Ab initiodefect energetics of perovskite (001) surfaces for solid oxide fuel cells: A comparative study ofLaMnO3versusSrTiO3andLee1, Morgan2 2015Phys. Rev. B433360View full textAdd to dashboardCite

“…We note that while these cleaved surfaces are certainly oversimplified for LaAlO 3 [33,34] and SrTiO 3 [35], it is quite possible that these are the correct surface for LSM/LaMnO 3 . These surfaces have been predicted to be a possible stable surface structure [39,42,43] under solid oxide fuel cell operating conditions and have been found experimentally for similar systems both at low temperature and high temperature in recent studies [44][45][46][47]. This paper demonstrates how facile charge motion can stabilize LaMnO 3 /LSM surface without significant atomic reconstruction, thereby further supporting the use of these ideal surfaces.…”

Fermi surface reconstruction of superoxygenated La2CuO4superconductors with ordered oxygen interstitials

“…[18][19][20] Electronic structure calculations show that the displacement of apical oxygen, due to oxygen defects, changes the spin-phonon coupling 21 and the electronic states near the Fermi level in cuprates. 22 The control of the functional electronic properties via dopant manipulation is of very high interest in manganites 23 and graphene. 24 The focus has been recently addressed to the control of structural nanoscale phase separation into dopant-rich puddles embedded in a dopant-poor background in these complex materials.…”

Resistive switching behavior of BaTiO3/La0.8Ca0.2MnO3 heterostructures

“…The physical origin of RS effect in manganites is attributed to local changes of oxygen vacancy concentration at the interface of metal/manganites induced by electrical perturbation [15,16]. Recently, Bryant et al provide direct image of oxygen defects and their motion at a manganite surface by using scanning tunneling microscopy [17]. In manganites the delicate balance between electronic phases is sensitive to external perturbation including the applications of electric/magnetic fields or pressure.…”