The magnetism in heavily Dy doped La0.7-xDyxSr0.3MnO3(0.40≤x≤0.70)system is studied in this paper.The M-T relation seems to be complicated with the increase of x.For sample with x=0.40,AFM behavior exists at T≤TN and M-T curves under zero field cooling(ZFC)and field cooling(FC)exhibit typical behavior of spincluster glass state above TN.For the sample with x=0.50,the M-T curve under ZFC exhibits a valley at a low temperature while the M-T curve under FC exhibits the negative magnetization below TN.For samples with x=0.60,0.70,their ZFC M-T curves are similar to that of x=0.50,but the FC M-T curves do not exhibit negative values any more.All the peculiar phenomena above are well explained by Néel double-lattice model combined with M-H relation at typical temperatures.The molecular field theory fits well the negative magnetization for x=0.50.
LIU Ning 1,2 ,YAN GuoQing 1,3 ,CAI ZhiRang 1 ,PI Li 2 ,ZHANG Bei 2 &TONG Wei 2 1 Department of Physics,Suzhou College,Suzhou 234000,China
