Formation of magnetic polarons in lightly Ca doped LaCoO3

Conference · Mon Feb 01 04:00:00 EST 2010

DOI:https://doi.org/10.1088/1742-6596/200/1/012080· OSTI ID:973837

Kataev, Vladislav ^[1]; Alfonsov, Aleksei ^[1]; Vavilova, Eugenia ^[1]; Podlesnyak, Andrey A. ^[2]; Khomskii, D. I. ^[3]; Buchner, B ^[1]

---

1. IFW Dresden
2. ORNL
3. Universitat zu Koln (University of Cologne), Germany

We performed high field electron spin resonance, nuclear magnetic resonance and static magnetization measurements on a powder sample of lightly hole-doped La{sub 1-x}Ca{sub x}CoO{sub 3}, x {approx} 0.002 in order to study the influence of the size of the substitution ion on the formation of the hole induced spin-state polaron. Previous works showed that doping of LaCoO{sub 3} with Sr in very small concentrations (x {approx} 0.002) yields the formation of a magnetic polaron with a big spin value and large spin orbital coupling. The Ca{sup 2+} ion, in contrast to the Sr{sup 2+} ion, has almost the same ionic radius as the La{sup 3+} ion. Therefore, the substitution of Ca for La provides mainly a hole to the system without creation of a sizeable crystal field distortion around the substituted Ca ion. The data obtained on La{sub 0.998}Ca{sub 0.002}CoO{sub 3} provide experimental evidence that the introduced hole indeed plays the main role in the formation of the spin-state polaron. Accompanying crystal field distortions seem to play a minor role, e.g. influencing the fine splitting of the spin polaron energy levels and the contribution of the spin orbital coupling.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 973837
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CRYSTAL FIELD
ELECTRON SPIN RESONANCE
ENERGY LEVELS
MAGNETISM
MAGNETIZATION
NUCLEAR MAGNETIC RESONANCE
POLARONS
SPIN