https://doi.org/10.1007/s100510051059
Charge-carrier density collapse in La0.67Ca0.33MnO3 and La0.67Sr0.33MnO3 epitaxial thin films
1
Institut für Physik, Johannes Gutenberg-Universität Mainz,
55099 Mainz, Germany
2
Research Institute for Materials and High Field Magnet Laboratory,
University of Nijmegen, 6252 ED Nijmegen, The Netherlands
Received:
22
July
1999
Revised:
7
October
1999
Published online: 15 April 2000
We measured the temperature dependence of the linear high field Hall resistivity
of 
(
K) and
(
K) thin films in the temperature range from 4 K up to 360 K in
magnetic fields up to 20 T. At low temperatures we find a charge-carrier density of 1.3 and 1.4 holes per unit cell
for the Ca- and Sr-doped compound, respectively. In this temperature range electron-magnon
scattering contributes to the longitudinal resistivity.
At the ferromagnetic transition
temperature TC a dramatic drop in the number of charge-carriers n down to 0.6 holes per unit cell,
accompanied by an increase in unit cell volume, is observed.
Corrections of the Hall data due to a non saturated magnetic state will lead a more pronounced charge-carrier density
collapse.
PACS: 71.38.+i – Polarons and electron-phonon interactions / 73.50.Jt – Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects) / 75.30.Vn – Colossal magnetoresistance
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000
