摘要
尖晶石型铁氧体是十分重要的磁性材料之一,具有独特的物理性质、化学特性、磁学特性和电子特性.其中尖晶石型钴铁氧体具有较好的电磁性质而被广泛应用.本文基于密度泛函理论(DFT)的第一性原理平面波赝势法,结合广义梯度近似(GGA+U),研究了Co RE0.125Fe1.875O4(RE=Nd,Eu,Gd)体系的电子结构和磁性能.结果表明随着稀土元素从Nd到Gd掺杂体系晶胞的晶格常数呈递减趋势.磁性能依赖于稀土离子(RE3+)4f轨道未配对的电子数,掺杂Eu和Gd能够提高钴铁氧体体系的磁矩,主要因为它们3+价态离子具有较多未配对的4f电子,因而对磁性能的影响较大.然而Nd的掺杂对体系磁性能的影响很小,这是由于它的离子半径较大,导致晶格发生畸变.
Spinel ferrite is one of the very important magnetic materials, having the unique physical properties, chemical properties, magnetic properties, and electronic properties. Co Fe2O4 is widely used due to their good electromagnetic properties. We have studied the electronic structure and magnetic properties of Co RE0.125Fe1.875O4（RE = Nd, Eu,Gd）by first-principles plane-wave pseudopotential method based on density functional theory（DFT）, combined with the generalized gradient approximation（GGA ＋ U） in this paper. Results show that the lattice constants of the compunds Co Fe1.875RE0.125O4（RE=Nd, Eu and Gd） will decrease due to the decreasing ionic radius of RE as the atomic number increases. Their magnetic properties depend on the unpaired 4f electrons of RE3＋ions, and the net magnetic moment of Co Fe2O4 will increase with Eu and Gd doping, mainly because there are more unpaired 4f electrons in Eu3＋and Gd3＋. Thus the doping of Eu3＋and Gd3＋may have a greater impact on the magnetic properties of cobalt ferrite. The contribution from the doping of Nd is not remarkable on the magnetic properties, since the Nd3＋ion, having a larger ionic radius, could distort the crystal structure of Co Fe2O4.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2015年第3期446-451,共6页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11304146
51401103)
江西省教育厅基金(批准号:GJJ13484)资助的课题~~
关键词
尖晶石型钴铁氧体
第一性原理
电子结构
磁性能
spinel cobalt ferrite
first-principles
electronic structure
magnetic properties
