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Title: Changes in the electronic structure and spin dynamics across the metal-insulator transition in LaLa 1-xSr xCoO 3

The magnetoelectronic properties of La 1-xSr xCoO 3, 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 x C ~ 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 < x C to Korringa-like ferromagnetic metal behavior for x > x C. A marked decrease in the spin-lattice relaxation rate is found in the vicinity of x C 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