The midinfrared anomalous Hall effect (AHE) can provide critical new information for resolving the controversial origins of the dc AHE in Ca xSr1-xRuO3. The complex Faraday and Kerr angles, as well as the complex Hall conductivity σxy, are measured in CaxSr1-xRuO3 films as a function of mid- and near-infrared energy E from 0.1 eV to 1.4 eV, magnetic field H, temperature T, and Ca concentration x. For the ferromagnetic state from x=0 to 0.4, the (dxz,dyz)-orbital tight-binding model is employed to investigate the quasiparticle role in the low energy response of the AHE σxy(E) since the Berry curvature term becomes weak at low energies. The infrared Hall sign reversals with T are observed only at x=0 and 0.13, which is narrower than the Ca concentration range in which the dc Hall sign reversal appears. The similarity of the infrared Hall angles between paramagnetic and ferromagnetic CaxSr1-xRuO3 compounds demonstrates the symmetric nature of the Hall response around the quantum phase transition at x=0.7.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Oct 1 2013|