| Автор | A Peles |
| Автор | H P Kunkel |
| Автор | X Z Zhou |
| Автор | Gwyn Williams |
| Дата выпуска | 1999-10-18 |
| dc.description | A summary of detailed measurements of the field and temperature dependence of the ac susceptibility, magnetization and the longitudinal and transverse magnetoresistivities of ceramic La<sub>0.67</sub>Pb<sub>0.33</sub>MnO<sub>3</sub> is presented. Detailed analysis of the magnetic data provides an estimate of 340.5±0.5 K for the paramagnetic to ferromagnetic transition temperature T<sub>c</sub>, with the data closest to the critical point yielding = 1.39±0.06 (from the temperature dependence of the susceptibility along the crossover line), = 0.41±0.02 (from the field induced variation of the temperature of the same line) and = 4.20±0.15 (from the field dependence of the critical isotherm). Nevertheless the presence of disorder - a variance in the distribution of spin-spin coupling strengths - means that Heisenberg model (asymptotic) exponents cannot be excluded; the universality class for this system cannot therefore be definitively identified. The transport data yield T<sub>c</sub> = 339.6±0.4 K, and while the isotropic magnetoresistance peaks near T<sub>c</sub>, as expected, the magnitude of the spontaneous resistive anisotropy (SRA) (the difference between the longitudinal and transverse magnetoresistance extrapolated to zero induction) increases linearly with decreasing temperature below T<sub>c</sub>, peaks near 30 K and then falls to a smaller value (-0.2±0.03%) in the liquid helium range. While this latter value is in reasonable agreement with itinerant model predictions, the temperature variation in the SRA above 30 K is more convincingly reproduced by a localized model. Furthermore, the mechanisms controlling the isotropic magnetoresistance and the SRA in this system appear to be different. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Field-dependent magnetic and transport properties and anisotropic magnetoresistance in ceramic La<sub>0.67</sub>Pb<sub>0.33</sub>MnO<sub>3</sub> |
| Тип | paper |
| DOI | 10.1088/0953-8984/11/41/314 |
| Electronic ISSN | 1361-648X |
| Print ISSN | 0953-8984 |
| Журнал | Journal of Physics: Condensed Matter |
| Том | 11 |
| Первая страница | 8111 |
| Последняя страница | 8130 |
| Аффилиация | A Peles; Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada |
| Аффилиация | H P Kunkel; Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada |
| Аффилиация | X Z Zhou; Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada |
| Аффилиация | Gwyn Williams; Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada |
| Выпуск | 41 |
