- Tytuł:
- Effect of Alloying with Ca in LaMnO$\text{}_{3}$ System Studied by KKR-CPA Method and Giant Magnetoresistance
- Autorzy:
-
Tobola, J.
Kaprzyk, S.
Pierre, J. - Powiązania:
- https://bibliotekanauki.pl/articles/1964825.pdf
- Data publikacji:
- 1997-08
- Wydawca:
- Polska Akademia Nauk. Instytut Fizyki PAN
- Tematy:
-
71.20.-b
71.20.Lp - Opis:
- La$\text{}_{1-x}$ Ca$\text{}_{x}$MnO$\text{}_{3}$ perovskites show semiconducting properties in the paramagnetic range. The gap is reduced near x=0.33, where ferromagnetic ordering is observed. The ferromagnetic ordering then induces a semiconductor-metal transition, and gives rise to a giant magnetoresistance effect. The ground state electronic structure calculations were done with KKR-CPA method for hypothetical cubic and ferromagnetic LaMnO$\text{}_{3}$ and CaMnO$\text{}_{3}$ compounds, as well as for disordered La$\text{}_{1-x}$Ca$\text{}_{x}$MnO$\text{}_{3}$ (x=0.33, 0.4, 0.5) alloys with real crystal data. As a result, we get a magnetic moment per formula 4.00μ$\text{}_{B}$ and 3.00μ$\text{}_{B}$ and half-metallic behaviour for end-compounds, respectively. In the ferromagnetic region a linear decrease in the magnetic moment of La$\text{}_{1-x}$Ca$\text{}_{x}$MnO$\text{}_{3}$ is observed, together with the decrease in the gap width for spin-down carriers, if doping Ca in La$\text{}_{1-x}$Ca$\text{}_{x}$MnO$\text{}_{3}$. A simple model is developed, which describes magnetic and transport properties as resulting from an exchange-induced band-crossing semiconductor-metal transition, as for instance in EuO.
- Źródło:
-
Acta Physica Polonica A; 1997, 92, 2; 461-464
0587-4246
1898-794X - Pojawia się w:
- Acta Physica Polonica A
- Dostawca treści:
- Biblioteka Nauki
Artykuł