Chemical potential shift induced by double-exchange and polaronic effects inNd1−xSrxMnO3

Abstract

We have studied the chemical potential shift as a function of temperature in Nd1−xSrxMnO3 (NSMO) by measurements of core-level photoemission spectra. For ferromagnetic samples (x = 0.4 and 0.45), we observed an unusually large upward chemical potential shift with decreasing temperature in the low-temperature region of the ferromagnetic metallic (FM) phase. This can be explained by the double-exchange (DE) mechanism if the eg band is split by dynamical/local Jahn-Teller effect. The shift was suppressed near the Curie temperature (TC ), which we attribute to the crossover from the DE to lattice-polaron regimes.

Chemical potential landscape in band filling and bandwidth-control of manganites: Photoemission spectroscopy measurements

“…Therefore, we attribute the upward shifts with increasing bandwidth to the double-exchange interaction with the Jahn-Tellersplit e g band as shown in Fig. 4(f), consistent with the temperature-dependent ∆µ [10].…”

“…∆µ in LSMO, which has the widest bandwidth among the manganites, exhibited a monotonous shift without indication of chemical potential pinning, reflecting that there is no intrinsic stripe formation in LSMO [8,9]. As for the effect of double-exchange interaction on ∆µ, an upward ∆µ with decreasing temperature has been found in the low-temperature part of the ferromagnetic metallic (FM) phase and attributed the shift to the change of bandwidth under Jahn-Teller-split e g band induced by double-exchange interaction [10]. This observation is consistent with the theoretical prediction using oneorbital double-exchange model by Furukawa [11].…”

“…In the composition range 0.3 < x < 0.5 where the FM phase appears, one can see an upward shift ∆µ − ∆µ with increasing r A and hence increasing bandwidth. The upward ∆µ with decreasing temperature has been observed in the low-temperature region of the FM phase of NSMO with x = 0.4 and 0.45 because of doubleexchange interaction with the Jahn-Teller-split e g band [10]. Furukawa [11] has predicted theoretically using the one-orbital model that in a double-exchange system a large upward ∆µ occurs with decreasing temperature in the FM phase due to the increase of the bandwidth.…”

Facile Synthesis, Magnetic and Electric Characterization of Mixed Valence La0.75K0.25AMnTiO6 (A = Sr and Ba) Perovskites

“…The XPS results revealed that the binding energy of Ti 2p 3/2 (458.1 eV for La 0.75 K 0.25 SrMnTiO 6 and 458.0 eV for La 0.75 K 0.25 BaMnTiO 6 ) corresponds to that of previously reported Ti 4+ oxidation state 31 and the binding energy of Mn 2p 3/2 (642.3 eV for La 0.75 K 0.25 SrMnTiO 6 and 642.2 eV for La 0.75 K 0.25 BaMnTiO 6 ) is an intermediate value between those of Mn 3+ and Mn 4+ . 32 Therefore, the valence of Ti atoms is tetravalent, whereas that of the Mn atoms is a mixed Mn 3+ /Mn 4+ , which is consistent with the charge neutrality calculated for the title compounds. The XPS spectra of K 2p, La 3d, Sr 3d, Ba 3d, and O 1s qre given in Figure S1.…”

XPS study of Pr1−xCaxMnO3 (x=0.2, 0.33, 0.4 and 0.84)

“…From the core level studies of CMR systems, there are many reports regarding the chemical potential shifts [20][21][22] as a function of concentraions at room temperature. But a few study has been reported at low * Corresponding author.…”