Effects of dopants and oxygen non-stoichiometry on thermodynamic and magnetic properties of micro- and nanostructured perovskite type manganites
| Autor: | M. Urse, Florina Teodorescu, H. Chiriac, Speranta Tanasescu, M. N. Grecu, Nicolae Totir, L. M. Giurgiu |
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| Rok vydání: | 2009 |
| Předmět: |
Materials science
Electromotive force Condensed matter physics Doping chemistry.chemical_element Thermodynamics EMF measurement Polaron Oxygen Industrial and Manufacturing Engineering law.invention chemistry law Ceramics and Composites Electron paramagnetic resonance Stoichiometry Perovskite (structure) |
| Zdroj: | Advances in Applied Ceramics. 108:273-279 |
| ISSN: | 1743-6761 1743-6753 |
| DOI: | 10.1179/174367609x414044 |
| Popis: | The aim of the paper is to evidence the effect of the composition and oxygen stoichiometry on the thermodynamic, spin dynamics and magnetic properties of some micro- and nanostructured substituted manganites La1–xAxMn1–yByO3–δ (A=Ca; B=Co, Fe; x=0·33; y=0, 0·02 and 0·04). The partial molar thermodynamic properties of oxygen dissolution in the perovskite phase as well the equilibrium partial pressures of oxygen have been obtained using solid electrolyte electrochemical cells [electromotive force measurement (EMF)] method. The influence of the oxygen stoichiometry change on the thermodynamic properties was examined using the data obtained by a coulometric titration technique coupled with EMF measurements. Using electron paramagnetic resonance spectroscopy, the spin dynamics has been investigated. Particular attention was devoted to the discussion concerning the influence of doping on polaron activation energy E a and exchange coupling integral J between Mn spins. The results were correlated with the... |
| Databáze: | OpenAIRE |
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