Metastable magnetic behavior in La_0.9Tb_0.1MnO₃

The linear and nonlinear magnetizations of La_0.9Tb_0.1MnO₃ at low temperatures were reported in detail. The temperature dependence of magnetization shows peaks at 50, 100 and 150 K, respectively. When LaMnO₃ is Tb-doped, its magnetic structure exhibits a canted antiparallel spin order. This is different from classical antiferromagnetic (AFM) in which the relaxation behavior takes place at about 150 K. At 50 K, Tb-doped LaMnO₃ exhibits canonical spin glass behavior, arising from the competition of exchange and super-exchange between spins. The peak at 100 K shows neither spin glass behavior nor canted AFM behavior. Its peak value increases with frequency increasing, and the transition temperature of the peak shifts to higher temperatures with frequency increasing. The study of aging behavior at 100 K shows a periodical variable metastability, which is ascribed to the competition between ferromagnetic (FM)-, AFM- and sinusoidal-order interactions. This work should shed a light on understanding the complex magnetic structure of the perovskite oxides.