中文摘要：

采用传统固相反应法制备La1.1Dy0.1Sr1.8Mn2O7多晶样品,并通过测量样品的磁化强度随温度变化曲线（M-T）以及磁化强度随外加磁场的变化曲线（M-H）对样品的磁性进行了研究。结果表明,在整个温度测量范围内,随温度的降低,样品的磁性发生了多次转变,在类Griffiths相温度（TG≈350 K）以上,样品处于纯顺磁态;在三维铁磁有序温度T3D（≈187 K）至TG温度范围内,样品处于铁磁-顺磁共存态;在奈尔温度TN（≈165 K）至T3D温度范围内,样品的铁磁性随着温度的降低逐渐增强;在TN温度以下,样品的反铁磁性增强而铁磁性减弱,表现出了反铁磁和铁磁相互竞争的现象。另外,通过居里外斯拟合以及Griffiths相模型拟合,发现样品在TG以下存在类Griffiths相。

英文摘要：

The polycrystalline samples of double -layered manganite La1.1,Dy0.1Sr1.8 Mn2O7 were prepared by the tradition- al solid state reaction method. Magnetic properties of the sample were investigated by measuring the magnetization - tempera- ture （M- T） and magnetization -field （M- H） curves. Experimental results show that, in the whole temperature range, there are multiple magnetic transitions occur with decreasing temperatures in the sample. Above the Griffiths - like temperature TG （TG ≈350 K）, the samples enter a pure paramagnetie state ; In the temperature range T3D -TC, coexistence of ferromag-netic and paramagnetic characteristics is observed, where T3D ≈ 187 K is the two -dimensional ferromagnetic order tempera- ture; In the temperature range TN - T3D, the ferromagnetism gradually enhances with decreasing temperatures , where TN 165 K is the Neel temperature; At temperatures below TN, the antiferromagnetism enhances and the ferromagnetism reduces, and the interplay between antiferromagnetic and ferromagnetic exchange couplings appears in the sample. In addition, through the Curie - Weiss and Griffiths model fitting, it＇ s found the Griffiths - like phase exist below TG.