Magnetoconductivity and Hall effects in La0.67Ca0.33MnO3

G. Jeffrey Snyder, M. R. Beasley, T. H. Geballe, Ron Hiskes, Steve DiCarolis
1996 Applied Physics Letters  
The observed H 2 and ͉H͉ dependence of the magnetoresistance above and below T C , respectively, may be explained by general time-reversal symmetry considerations. We further find empirically that the saturation observed in the magnetoresistance is best fit by a simple resistor in series with a magnetoconductor: (H)ϭ ϱ ϩ1/( 0 ϩ␥͉H͉) for TϽTc and (H)ϭ ϱ ϩ1/( 0 ϩ␤H 2 ) for T ϾT C . This provides a functional form to analyze and predict the magnetoresistance over a wide range of fields. This
more » ... fields. This suggests that the underlying mechanism of "colossal magnetoresistance " may be magnetoconductive, not magnetoresistive. The magnetoresistance and Hall effects on an annealed epitaxial thin films of La 0.67 Ca 0.33 MnO 3 were measured at 0.9 T C and 1.1 T C . At low fields, anisotropic magnetoresistance plays a dominant role. The high field Hall effect shows holelike carriers above and below T C . The apparent change in sign at low fields is likely due to the anomalous Hall effect.
doi:10.1063/1.116962 fatcat:u475gzwtvnbmhbmksw5grdwcpy