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Title: Changes in the electronic structure and spin dynamics across the metal-insulator transition in LaLa1-xSrxCoO3

The magnetoelectronic properties of La1-xSrxCoO3, which include giant magnetoresistance, are strongly dependent on the level of hole doping. The system evolves, with increasing x, from a spin glass insulator to a metallic ferromagnet with a metal-insulator (MI) transition at xC ~ 0.18. Nanoscale phase separation occurs in the insulating phase and persists, to some extent, into the just-metallic phase. The present experiments at 4.2 K have used 139La NMR to investigate the transition from hopping dynamics for x < xC to Korringa-like ferromagnetic metal behavior for x > xC. A marked decrease in the spin-lattice relaxation rate is found in the vicinity of xC as the MI transition is crossed. Lastly, this behavior is accounted for in terms of the evolution of the electronic structure and dynamics with cluster size.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2]
  1. Florida State Univ., Tallahassee, FL (United States). National High Magnetic Field Lab. (MagLab)
  2. Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
Publication Date:
Grant/Contract Number:
AC02-06CH11357; DMR-1157490
Type:
Accepted Manuscript
Journal Name:
Physical Review, B: Condensed Matter
Additional Journal Information:
Journal Volume: 93; Journal Issue: 2; Journal ID: ISSN 0163-1829
Publisher:
American Physical Society (APS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE
OSTI Identifier:
1339091
Alternate Identifier(s):
OSTI ID: 1235970