| Autor: |
Trukhanov, S. V., Lobanovski, L. S., Bushinsky, M. V., Khomchenko, V. A., Pushkarev, N. V., Troyanchuk, I. O., Maignan, A., Flahaut, D., Szymczak, H., Szymczak, R. |
| Předmět: |
|
| Zdroj: |
European Physical Journal B: Condensed Matter; Nov2004, Vol. 42 Issue 1, p51-61, 11p, 2 Charts, 10 Graphs |
| Abstrakt: |
The crystal structure, magnetization and electrical transport depending on the temperature and magnetic field for the doped stoichiometricas well as anion-deficient() ortomanganite systems have been experimentally studied. It is established that the stochiometric samples in the region of theare an-orthorhombic perovskites whereas in the- a rhombohedric. For the anion-deficient system the symmetry type of the unit cell is similar to the stoichiometric one. As a doping level increases the samples in the ground state undergo a number of the magnetic transitions. It is assumed that the samples with the large amount of oxygen vacancies are a cluster spin glasses () and temperature of the magnetic moment freezing is ~40 K. All the anion-deficient samples are semiconductors and show considerable magnetoresistance over a wide temperature range with a peak for thex= 0.175 only. Concentration dependences of the spontaneous magnetization and magnetic ordering temperature for the anion-deficientsystem have been established by the magnetic measurements and compared with those for the stoichiometricone. The magnetic propeprties of the anion-deficient samples may be interpreted on the base of the superexchange interaction and phase separation (chemical disorder) models. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
