Nonlinear magneto-optical properties of colossal magnetoresistive manganites

Pr1-xCaxMnO3 and Nd1-xSrxMnO3 were investigated with three-photon differenc e frequency generation (DFG). This method allows one to determine both the crystalline and the magnetic symmetry. In the highly ordered low-temperatur e phase of Nd0.50Sr0.50MnO3, a DFG contribution coupling simultaneously to antiferromagnetic and charge ordering was observed and used to reveal the f ormation of domains. Thus, magnetically induced three-photon processes are introduced into the fields of both nonlinear magnetooptics and colossal mag netoresistance as a powerful new method.