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K2NiF4型钴氧化物的自旋态转变及准二维层状结构使其具有独特的磁学性质,开展不同稀土离子掺杂对Ln0.8Sr1.2CoO4结构与磁性的影响研究可更好地揭示维度特性对其物理性质的影响.文章基于固相反应法合成的Ln0.8Sr1.2CoO4(Ln=La,Nd,Gd)多晶样品,围绕空穴掺杂对结构的影响及其低温下复杂的磁性,通过物性测试系统对系列样品进行直流磁化强度的测试与分析,阐明了不同稀土离子掺杂对该体系结构与磁性的影响.结果表明:随着体系中A位平均离子半径的减小,晶胞参数减小,Jahn-Teller畸变增大,Griffiths相温度由214.9 K降低到159.9 K,外斯温度由89.4 K降低到7.1 K,表明体系的铁磁性被抑制而反铁磁性逐渐增强;低温区稀土离子对磁化强度的贡献愈加明显,Gd0.8Sr1.2CoO4样品的磁矩高达36.42×10-3 emu/mol;Ln0.8Sr1.2CoO4体系内部化学压力效应的改变诱导更多低自旋态Co3+稳定,进而导致磁状态的改变.“,”K2 NiF4 type cobalt oxide usually shows many unique magnetic properties due to spin state transition and its quasi two dimensional layered structure.On account of hole doping effect on structure and their intricate low temperature magnetic properties,the Ln0.8 Sr1.2 CoO4 (Ln =La,Nd, Gd)samples were prepared with conventional solid state reaction method.The dc magnetization was carried out using the physical properties measurement system of quantum design.The relationship between the structure and magnetic properties in Ln0.8 Sr1.2 CoO4 was systematically studied.With the decrease of the average A-site ionic radius,the lattice parameters decrease,the Jahn-Teller distortion is enhanced,the Griffiths temperature decreases from 214.9 K to 159.9 K,and the Weiss temperature decreases from 89 .4 K to 7 .1 K,which suggests the suppression of ferromagnetism as well as the enhancement of antiferromagnetism.In the lower temperature region,the contribution of rare earth ions to the magnetization of samples is more obvious.The magnetization of Gd0.8 Sr1.2 CoO4 reaches to 36.42 emu/mol.Meanwhile,the change of chemical pressure effect leads to more low spin state of Co3+ions in Ln0.8Sr1.2CoO4,which results in the change of the magnetic state.