Transverse Kerr effect in the (La1-xPrx)(0.7)Ca0.3MnO3 ceramics

Magneto-optical properties were measured for (La1-xPrx)(0.7)Ca0.3MnO3 (x = 0, 0.25, 0.5, 0.75, I)ceramic solid solutions, including temperature, magne tic field, oxygen isotope content and spectral dependences of the transvers e Kerr effect (TKE). The TKE spectra after the transition to the ferromagne tic metallic state depend only weakly on the substitution of La for Pr as l ong as x less than or equal to 0.5. A surface magnetism contribution result s in a TKE peak near T-C but it can be suppressed by magnetic field or a lo ng-time annealing. A significant oxygen isotope effect is observed for all compositions, being critical for x = 0.75. Hysteresis phenomena of two diff erent types were observed in the temperature dependences of TKE. The first type, related to the ferromagnetic fluctuations, was found for x less than or equal to 0.5 (TKE is larger on cooling). The second type was related to the magnetically inhomogeneous state for x = 0.75 and 1 (TKE is larger on h eating). The hysteretic variations in me magneto-optical spectrum of (La0.2 5Pr0.75)(0.7)Ca0.3MnO3 are referred to the possible charge carrier redistri bution between the incipient ferromagnetic component and the charge ordered antiferromagnetic component.