EPR study of solid solutions La1-0.33yBa0.33yMn yAl1-yO3 (y = 0.02, 0.04, 0.10)

Abstract

Abstract-Solid solutions La1-0.33yBa0.33yM nyAl1-yO3 (y = 0.02, 0.04, 0.10) prepared using the ceramic technique have been investigated by the EPR method at temperatures of 77 and 300 K. By comparing with the calculated spectra, the experimental spectra have been assigned to Mn2+ ions (g = 2.04 and line width δHpp = 64 × 10-4 T at T=77K) and Mn 4+ ions (g = 1.97 and δHpp = 76 × 10 -4 T at T = 77 K) and the broad line (δHpp = 500 × 10-4 T at T = 77 K) has been attributed to clusters. The dilution of manganese ions as a result of the dissolution of La 0.67Ba0.33MnO3 in LaAlO3 has allowed one to trace the cluster formation and the spin dynamics of Mn ions. It has been established that, at room temperature, compared to the system in which the Sr2+ ion with a smaller ionic radius is the replacing element, the localized states are more stable at all three manganese concentrations (the EPR lines are more intense). The La0.67Ba0.33MnO3 clusters dissolved in LaAlO3 retain some properties of a concentrated compound even upon dilution to y = 0.02. © Pleiades Publishing, Ltd., 2010.