Carrier density variation in films of
Laboratorium voor Vaste-Stoffysica en Magnetisme, Katholieke Universiteit
Celestijnenlaan 200 D, 3001 Leuven, Belgium
2 Instituut voor Kern- en Stralingsfysica, Katholieke Universiteit Leuven Celestijnenlaan 200 D, 3001 Leuven, Belgium
Accepted: 14 November 1997
The carrier density in thin films of , as derived from Hall measurements, shows a distinct change at the paramagnetic (PM)-ferromagnetic (FM) transition around . In the PM-semiconducting regime the density is n = 0.30 holes per unit cell and increases in the FM-semimetallic regime to n = 0.49. The magnetoresistance effect in the semimetallic phase is due to a field-induced increase of the carrier mobility, while the carrier density is unaffected. In the low-field limit an extraordinary enhancement of the slope due to the anomalous Hall effect is observed. The spontaneous Hall resistivity , reflecting the strength of the asymmetric scattering between carriers and localized magnetic moments, is linked to the zero-field resistivity via .
PACS: 73.50.Jt – Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects) / 75.70.Ak – Magnetic properties of monolayers and thin films / 75.70.Pa – Giant magnetoresistance
© EDP Sciences, 1998