Spin-state polarons in lightly-hole-doped LaCoO3.
Inelastic neutron scattering (INS), electron spin resonance (ESR), and nuclear magnetic resonance (NMR) measurements were employed to establish the origin of the strong magnetic signal in lightly-hole-doped La1-xSrxCoO3, x approximately 0.002. Both INS and ESR low temperature spectra show intense excitations with large effective g factors approximately 10-18. NMR data indicate the creation of extended magnetic clusters. From the Q dependence of the INS magnetic intensity, we conclude that the observed anomalies are caused by the formation of octahedrally shaped spin-state polarons comprising seven Co ions. The present INS, ESR, and NMR data give evidence for two regimes in the lightly-hole-doped samples: (i) T<35 K dominated by spin polarons; (ii) T>35 K dominated by thermally activated magnetic Co3+ ions.
Podlesnyak
A
A
Hahn-Meitner-Institut, Glienicker Strasse 100, Berlin 14109, Germany. podlesnyakaa@ornl.gov
Russina
M
M
Furrer
A
A
Alfonsov
A
A
Vavilova
E
E
Kataev
V
V
Büchner
B
B
Strässle
Th
T
Pomjakushina
E
E
Conder
K
K
Khomskii
D I
DI