Mn${}^{2+}$/Mn${}^{3+}$ state of La${}_{0.7}$Ce${}_{0.3}$MnO${}_3$ by oxygen reduction and photodoping

Abstract

Films of cerium-doped LaMnO${}_3$, which has been intensively discussed as an electron-doped counterpart to hole-doped mixed-valence lanthanum manganites during the past decade, were analyzed by x-ray photoemission spectroscopy with respect to their manganese valence under photoexcitation. The comparative analysis of the Mn 3s exchange splitting of La${}_{0.7}$Ce${}_{0.3}$MnO${}_3$ (LCeMO) films in the dark and under illumination clearly shows that both oxygen reduction and illumination are able to decrease the Mn valence towards a mixed 2$+$/3$+$ state, independently of the film thickness and the degree of CeO${}_2$ segregation. Charge injection from the photoconductive SrTiO${}_3$ substrate into the Mn e${}_g$ band with carrier lifetimes in the range of tens of seconds and intrinsic generation of electron-hole pairs within the films are discussed as two possible sources of the Mn valence shift and the subsequent electron doping.

arXiv comment6 pages, 2 figures

References in corpus (5)

• Direct observation of electron doping in La0.7Ce0.3MnO3 using x-ray absorption spectroscopy
• Observation of minority spin character of the new electron doped manganite La_0.7Ce_0.3MnO_3 from tunneling magnetoresistance
• A 'p-n' diode with hole and electron-doped lanthanum manganite
• Photoemission and x-ray absorption spectroscopy study of electron-doped colossal magnetoresistance manganite: La0.7Ce0.3MnO3 film
• Transport, magnetic, and structural properties of La${}_{0.7}$Ce${}_{0.3}$MnO${}_3$ thin films. Evidence for hole-doping

Cited by in corpus (2)

• Electrical-transport characteristics of as-grown and oxygen-reduced La${}_{0.7}$Ce${}_{0.3}$MnO${}_3$ films: calculation of hopping energies, Mn valences, and carrier localization lengths
• Conductivity and magnetoresistance of La${}_{0.7}$Ce${}_{0.3}$MnO${}_3$ thin films under photoexcitation