Suppressed charge ordering and cluster glass behavior of Pr0.5Ca0.5Mn0.97Al0.03O3

The Pr0.5Ca0.5Mn0.97Al0.03O3 compound was prepared by standard solid-state reaction. The cusps of charge ordering and the long range AFM order of the “pseudo”-CE type are suppressed with Al impurity in Pr0.5Ca0.5MnO3. The ac susceptibility of Pr0.5Ca0.5Mn0.97Al0.03O3 at low temperatures is investigated. The real component χ\´ peak at the freezing temperature Tf is suppressed with increasing the frequency and shows a linear relation between Tf and the logarithm of the frequency. The normalized slope P = ΔTf/TfΔlog10 ω, which is much lower than canonical insulating spin glass systems in which 0.06 ≤ P ≤ 0.08. The intensity of χ" at Tf decreases with increasing frequency for ω ≤ 701 Hz and increases with further increasing frequency. This complex behavior is ascribed to the competition between the effects of large and little ferromagnetic clusters in the sample. The ground state is the transition state from cluster glass to phase separation. The AFM cluster blocking and the spin blocking were observed in the sample.