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Abstract

The electronic structure of La0.7Ce0.3MnO3 (LCeMO) has been investigated by using photoemission spectroscopy. A very weak 4f resonance is observed and the Ce 3d spectrum of LCeMO is very similar to that of CeO2, indicating that Ce ions are far from being trivalent. The Mn 2p core-level spectrum of LCeMO is essentially the same as that of hole-doped La0.7Sr0.3MnO3, but different from that of MnO. The local spin-density approximation (LSDA) electronic structure calculations for LCeMO show that the Mn 3d states contribute a large peak around -2 eV and a weak structure between -2 eV and EF, and that the O 2p states are spread between -3 eV and -9 eV, with negligible contribution near EF. The LSDA calculations for LCeMO and hole-doped La0.7Ba0.3MnO3 reveal that the calculated Mn 3d density of states at EF in LCeMO is larger, reflecting the effect of electron doping with Ce ions.

Photoemission and x-ray absorption spectroscopy study of electron-doped colossal magnetoresistive manganiteLa0.7Ce0.3Han1, Kang2, Kim3 et al. 2004Phys. Rev. B392180View full textAdd to dashboardCite

“…It is difficult to tell whether the resonance peak at hν ∼ 121 eV for BEs ≈ 1 − 2 eV has a Fano line-shape. This is because the enhancement is very weak and it overlaps with the strong La 5d resonance due to the La 4d → 4f RPES, which has a broad maximum around hν = 118 − 122 eV 5 . In order to examine the resonating features more clearly, we have compared the valence-band spectra around the two resonating hν values of hν ≈ 121 eV and hν ≈ 124 eV.…”

“…6 shows the extraction procedure of the Mn 3d partial spectral weight (PSW) of LCeMO. As a first approximation, the Mn 3d PSW of LCeMO is determined by subtracting the valence-band spectrum at hν = 25 eV, where the O 2p emission is dominant, from that at the off-resonance (hν = 115 eV) in Ce 4d → 4f RPES, where the Mn 3d and O 2p emissions are comparable each other 5 . The former spectrum has been scaled by a factor of ∼ 0.9 to account for the hν-dependence of the O 2p photoionization cross-section 23 .…”

The effect of grain size on electrical transport and magnetic properties of La0.9Te0.1MnO3

“…Although the focus of interest has primarily rested with the hole-doped manganites Ln 1-x A x MnO 3 (Ln = La-Tb, and A = Ca, Sr, Ba, Pb, etc.) due to their potential applications such as magnetic reading heads, field sensors and memories [1], naturally many researches have placed emphasis on electron-doped compounds such as La 1-x Ce x MnO 3 [2][3][4][5], La 1-x Zr x MnO 3 [6], La 2.3-x Y x Ca 0.7 Mn 2 O 7 [7], and La 1-x Te x MnO 3 [8][9][10] due to the potential applications in spintronics. These investigations also suggest that the CMR behavior probably occur in the mixed-valent state of Mn 2+ /Mn 3+ .…”

Electron- and Hole-Doping Effects in Manganites Studied by X-Ray Absorption Spectroscopy

“…This permits hopping of itinerant e g electrons between spin-aligned Mn 3+ and Mn 4+ ions and causes a DE interaction that results in an effective ferromagnetic interaction between Mn 3+ and Mn 4+ ions. Electron-doped manganites are obtained by doping Ce 4+ ions, in which similar DE interaction is expected between Mn 3+ and Mn 2+ ions [3,4,6,7]. According to these arguments, mixed-valence Mn charge states are responsible for correlation between magnetism and conductivity [1].…”

“…Extensive investigations were performed for the La 1jx Ca x MnO 3 compounds, which was called hole-doped manganites because Ca ions generated holes in LaMnO 3 (hereafter referred to as LM) [1,2]. In Ce doped LM, i.e., La 1jx Ce x MnO 3 , Ce ions donate electrons and are called electron-doped manganites [3,4]. The DE model was not satisfactory to explain metal-insulator and ferromagnetic transitions, and the concomitant colossal magnetoresistance phenomenon in the manganites [1,2].…”