Temperature dependent evolution of the electronic and local atomic structure in the cubic colossal magnetoresistive manganite La1-xSrxMnO3
We have studied the temperature-dependent evolution of the electronic and local atomic structure in the cubic colossal magnetoresistive manganite La{sub 1-x}Sr{sub x}MnO{sub 3} (x= 0.3-0.4) with core and valence level photoemission (PE), x-ray absorption spectroscopy (XAS), x-ray emission spectroscopy (XES), resonant inelastic x-ray scattering (RIXS), extended x-ray absorption fine structure (EXAFS) spectroscopy and magnetometry. As the temperature is varied across the Curie temperature T{sub c}, our PE experiments reveal a dramatic change of the electronic structure involving an increase in the Mn spin moment from {approx} 3 {micro}B to {approx} 4 {micro}B, and a modification of the local chemical environment of the other constituent atoms indicative of electron localization on the Mn atom. These effects are reversible and exhibit a slow-timescale {approx}200 K-wide hysteresis centered at T{sub c}. Based upon the probing depths accessed in our PE measurements, these effects seem to survive for at least 35-50 {angstrom} inward from the surface, while other consistent signatures for this modification of the electronic structure are revealed by more bulk sensitive spectroscopies like XAS and XES/RIXS. We interpret these effects as spectroscopic fingerprints for polaron formation, consistent with the presence of local Jahn-Teller distortions of the MnO{sub 6} octahedra around the Mn atom, as revealed by the EXAFS data. Magnetic susceptibility measurements in addition show typical signatures of ferro-magnetic clusters formation well above the Curie temperature.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- Advanced Light Source Division; Materials Sciences Division
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 928306
- Report Number(s):
- LBNL-239E; TRN: US0804324
- Journal Information:
- Physical Review B, Vol. 77; Related Information: Journal Publication Date: 2008
- Country of Publication:
- United States
- Language:
- English
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