Size dependences of crystal structure and magnetic properties of DyMnO3 nanoparticles
Size dependences of crystal structure and magnetic properties of DyMnO3 nanoparticles
复制标题
DyMnO3 纳米颗粒晶体结构和磁性能的尺寸依赖性
DOI：
10.1016/j.jmmm.2013.06.055
复制
发表时间：
2013
影响因子：
2.7
通讯作者：
A.Kohno
中科院分区：
文献类型：
--
作者：
T.Tajiri ;N.Terashita;K.Hamamoto;H.Deguchi;M.Mito;Y.Morimoto;K.Konishi;A.Kohno
我们在介孔氧化硅的孔中合成了粒径约为7.5-15.3 nm的DyMnO 3纳米颗粒，并对其晶体结构和磁性进行了研究。随着粒径的减小，DyMnO 3纳米颗粒的晶格常数偏离体相晶体的晶格常数，纳米颗粒体系中的Jahn-Teller畸变减小.此外，估计的晶格应变随着颗粒尺寸的减小而增加。DyMnO 3纳米粒子具有超顺磁性。阻断温度和矫顽场随颗粒尺寸的减小而增加，这种行为与通常的磁性尺寸效应相反。据推测，这些独特的尺寸依赖性的DyMnO 3纳米颗粒的磁性能来自晶格常数和晶格应变的变化。纳米颗粒的晶体结构中的各向异性晶格变形引起磁各向异性的增强，这导致阻挡温度和矫顽场随着颗粒尺寸的减小而增加。
We synthesized DyMnO3nanoparticles with particle sizes of about 7.5–15.3 nm in the pores of mesoporous silica and investigated their crystal structure and magnetic properties. As the particle size decreased, the lattice constants of the DyMnO3nanoparticles deviated from those of the bulk crystal, and the Jahn–Teller distortion in the nanoparticle systems decreased. In addition, the estimated lattice strain increased with decreasing particle size. The DyMnO3nanoparticles showed superparamagnetic behavior. The blocking temperature and the coercive field increased with decreasing particle size, and this behavior was contrary to the usual magnetic size effects. It is deduced that these unique size dependences of the magnetic properties for the DyMnO3nanoparticles were derived from the changes in lattice constants and lattice strain. The anisotropic lattice deformation in the crystal structure of the nanoparticles induces an enhancement of the magnetic anisotropy, which results in the increase in blocking temperature and coercive field with decreasing particle size.