Temperature dependent anomalous Hall effect in La-Ca-Mn-O films

The colossal magnetoresistance of La1-xCaxMnO3 has been reported in many ex periments. We present our study of the anomalous Hall effect in epitaxial L a0.67Ca0.33MnO3 thin films. We have measured the temperature dependence of resistivity, magnetization, and anomalous Hall effect coefficients between 300 and 5 K for our samples grown on different substrates. From these studi es, the relation between the resistivity and anomalous Hall effect coeffici ent as well as the temperature dependence of the anomalous Hall effect coef ficient are explored. Our results show that the direction of the anomalous Hall effect is reversed below approximately 100 K. This sign reversal is di scussed in terms of band structure and the coexistence of hole-like and ele ctron-like conduction. (C) 2000 American Institute of Physics. [S0021-8979( 00)33608-8].