【摘要】 利用x射线衍射和磁测量研究了不同稳定元素Co以及Ti,V和Cr替代对Nd3Fe2 9-x -yCoxMy(M =Ti,V ,Cr)化合物结构和磁性的影响 .研究发现 :每一个稳定元素都有一替代量极限 ,在此极限以内所有化合物均为Nd3(Fe,Ti) 2 9型结构 ,A2 m空间群 .不同稳定元素的溶解极限不同 .Co的替代量与稳定元素有关 ,当以Cr作为稳定元素时 ,Cr的替代量随着Co含量的提高而提高 ,直到得到纯Co基 3:2 9相化合物 .Ti和V作为稳定元素时 ,Co原子的最大替代量分别为 6 6 3和 12 所有Nd3(Fe ,Co ,M) 2 9(M =Ti,V ,Cr)化合物在室温下均表现为平面各向异性 .Nd3Fe2 6 8-xCoxV2 2 的居里温度TC和饱和磁化强度Ms随着Co含量的增加而单调增加 ,自旋重取温度随Co含量增加而呈上升趋势 ,但在x =6处有一最小值 ,这可能与Co的择优占位有关 ;而Nd3Fe2 9-x-yCoxCry的居里温度和饱和磁化强度随着Co含量的增加先增加后降低 ,只在x =0和x =6处观察到自旋重取向现象 .更多还原

【Abstract】 The effect of Co substitution and stabilizing elements on the structure and magnetic properties of Nd 3 Fe 29- x-y Co xM y(M =Ti,V,Cr) compounds was investigated by means of x-ray diffraction and magnetic measurements. The results show that all the synthesized compounds have been crystallized in Nd 3(Fe,Ti) 29 type structure with monoclinic symmetry and space group A2/m . The solution of Co element in the compounds is different for the different stabilizing elements. For Cr as the stabilizing element, the pure Co-based 3:29 phase could be obtained and the higher Cr content is required to stabilize the phase with increasing Co content. For Ti and V, the solution of Co in the compounds could be only 6 ^63 and 12 atoms, respectively. All the Nd 3(Fe, Co, M ) 29 compounds show easy-planar type anisotropy at room temperature. For the Nd 3(Fe,Co,V) 29 compounds, the Curie temperature and saturation magnetization increase first and then decrease with further increasing Co content. The spin reorientation temperature shows and increasing tendency except the minimum for x =6 due to the preferential occupation of Co atoms. For the Nd 3(Fe, Co, Cr) 29 compounds, the Curie temperature increases first and then decreases with increasing Co content, but the magnetization is diffcult to be saturated and only shows a decreasing tendency. The spin reorientation transition was only observed for the samples with x =0 and 6.更多还原