| Full text | |
| Author(s): |
Cabrera-Pasca, G. A.
[1]
;
Bosch-Santos, B.
[2]
;
Burimova, A. N.
[2]
;
Correa, E. L.
[2]
;
Carbonari, A. W.
[2]
Total Authors: 5
|
| Affiliation: | [1] Univ Fed Para, Fac Ciencias Exatas & Tecnol, BR-68440000 Abaetetuba, PA - Brazil
[2] IPEN CNEN SP, Inst Pesquisas Energet & Nucl, BR-05508000 Sao Paulo - Brazil
Total Affiliations: 2
|
| Document type: | Journal article |
| Source: | AIP ADVANCES; v. 10, n. 1 JAN 1 2020. |
| Web of Science Citations: | 0 |
| Abstract | |
LaMnO3+delta is a complex oxide, which, depending on the oxygen excess concentration, presents different crystalline structure and interesting magnetic and electric properties such as colossal magnetoresistance, polaron dynamics, multiferroic behavior, and charge-orbital ordering. This complexity requires different characterization techniques to draw a picture as complete as possible allowing a good understanding of these phenomena. Here, we have used the perturbed angular correlation (PAC) technique to measure hyperfine interactions at La and Mn sites of LaMnO3+delta(delta similar to 0.15) using Ce-140 and Cd-111 at La sites as probe nuclei in order to investigate within an atomic scale the magnetic and electric interactions in this compound. The results show that Cd-111 nuclei occupy highly symmetric local sites in agreement with a rhombohedral structure. The magnetic hyperfine field (B-hf) measured with Cd-111 at La sites is very small (B-hf = 0.40 T) due to the supertransferred magnetic field from Mn neighbors through oxygen orbitals. On the other hand, Ce-140 nuclei at La sites present a saturation field of around 3.7 T much higher than that expected for La sites (due to the weak transfer field by superexchange mechanism). In addition, for temperature range above the magnetic ordering (200-300 K) a dynamic hyperfine interaction was observed characterized by the attenuation parameter lambda(T) whose temperature dependence allowed to determine the activation energy (E-a) associated to charge transfer. The polarization of the 4f-electron of Ce impurities affects the local magnetic field at impurity sites as well as the E-a. (AU) | |
| FAPESP's process: | 19/15620-0 - Tuning MFe2O4 (M=Co,Ni) nanoparticles for in vivo biomedical applications: Doping with rare earths and biocompatible coating |
| Grantee: | Anastasia Nikolaevna Burimova |
| Support type: | Scholarships in Brazil - Post-Doctorate |
| FAPESP's process: | 14/14001-1 - Project and construction of a digital spectrometer:A more eficient equipment to investigate materials using PAC technique |
| Grantee: | Rajendra Narain Saxena |
| Support type: | Regular Research Grants |