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Nanostructures in calcia stabilized hafnia thin films observed by PAC as a function of temperature |
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| Authors: | M. C. Caracoche J. A. Martínez P. C. Rivas M. A. Taylor A. F. Pasquevich S. Barolin O. A. de Sanctis |
| Affiliation: | 1. Departamento de Física, FCE, Universidad Nacional de La Plata, IFLP, La Plata, Argentina 2. CICPBA, La Plata, Argentina 3. CONICET, La Plata, Argentina 4. Facultad de Ciencias Agronómicas y Forestales, Universidad Nacional de La Plata, IFLP, La Plata, Argentina 5. Lab. Materiales Cerámicos, FCEIyA—IFIR, Universidad Nacional de Rosario, Rosario, Argentina |
| Abstract: | The hyperfine quadrupole interaction at Hf sites in films and powders of 14 mol% CaO–HfO2 and 20 mol% CaO–HfO2 has been determined as a function of temperature. Results indicate the formation of a cubic solid solution and other microstructures assigned to the ?1 (CaHf4O9) and ?2 (Ca6Hf19O44) phases. Dynamical effects on the electric field gradient reveal the existence of oxygen vacancies movements in the solid solution. The thermal behavior of the relaxation constant observed in films allowed the determination of activation energies of 0.54 eV and 0.70 eV for the 14 mol% and 20 mol% CaO doped hafnias, respectively. The influence of the microdomains and the stability of the cubic solid solution are discussed. |
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