Electronic aspects of the ferromagnetic transition in manganese perovskites

Journal Article · Wed May 01 04:00:00 EDT 1996 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.76.4215· OSTI ID:285745

Park, J; Chen, C T; Cheong, S; Bao, W; Meigs, G; Chakarian, V; Idzerda, Y U ^[1]

---

1. AT&T Bell Laboratories, 600 Mountain Avenue, Murray Hill, New Jersey 07974 (United States)

We have investigated the electronic structure associated with the ferromagnetic transition of La{sub 1{minus}{ital x}}Ca{sub {ital x}}MnO{sub 3} and La{sub 1{minus}{ital x}}Pb{sub {ital x}}MnO{sub 3} using high resolution photoemission, Mn 2{ital p} resonant photoemission, and O 1{ital s} x-ray absorption spectroscopies. The data clearly show that the band gap collapses below the Curie temperature ({ital T}{sub {ital C}}) and the density of states at the Fermi level increases with cooling, providing a conclusive microscopic evidence for an insulator-metal transition. Our results suggest that strong small polaron effects, which mainly contribute a charge fluctuation energy of {approximately}1.5 eV, are responsible for the insulating behavior above {ital T}{sub {ital C}} which has been enigmatic in the double-exchange model. {copyright} {ital 1996 The American Physical Society.}

• Research Organization: Brookhaven National Laboratory
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 285745
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 22 Vol. 76; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTRA
CALCIUM OXIDES
DOPED MATERIALS
ELECTRONIC STRUCTURE
ENERGY-LEVEL DENSITY
LANTHANUM OXIDES
LEAD ADDITIONS
LEAD OXIDES
MANGANESE OXIDES
METAL-INSULATOR TRANSFORMATIONS
PHASE TRANSFORMATIONS
PHOTOEMISSION
SYNCHROTRON RADIATION
TEMPERATURE DEPENDENCE
X-RAY SPECTROSCOPY