Ni_(1-x)Mn_xO稀磁半导体的磁性研究  

Magnetic properties of Ni_(1-x)Mn_xO diluted magnetic semiconductor

作　　者：王超[1] 洪德雄 杨晓喻[1] 方明亮[1] 蔡亮[1] 陈琳[1] 闫文盛[1] 

机构地区：[1]中国科学技术大学国家同步辐射实验室,安徽合肥230029

出　　处：《中国科学技术大学学报》2014年第8期667-671,共5页JUSTC

基　　金：国家自然科学基金(U1332131)资助

摘　　要：通过X射线吸收近边结构(XANES)、超导量子干涉仪和第一性原理计算研究了脉冲激光沉积法(PLD)制备的Ni1-xMnxO(0.01≤x≤0.05)薄膜的微观结构和磁学性质.X射线吸收近边结构表明,当x≤0.03时,掺杂的Mn替代了NiO晶格中的Ni原子,并且以混合价态(+2/+3)的形式存在.当x>0.03时,掺杂的部分Mn离子形成了类Mn2O3杂相.磁性测量表明,随着Mn含量从0.01增加到0.03,Ni1-xMnxO薄膜的饱和磁矩从0.3μB/Mn增加到了0.45μB/Mn.基于第一性原理计算,我们提出Mn3+离子之间通过Ni空位表现出了铁磁性耦合,Mn2+离子之间则通过超交换作用表现出了反铁磁耦合.The microstructural and magnetic properties of Ni1 - xMnxO （0.01≤ x≤0.05） thin films prepared by pulsed laser deposition （PLD ） were studied by combining X-ray absorption near edge structure （XANES ） spectroscopy , superconducting quantum interference device （SQUID ） and first-principles calculations .XANES results at Mn K-edge show that at the low Mn doping level of x≤0.03 ,the Mn ions in the mixed oxidation valence state （＋2/＋3） are incorporated substitutionally into the NiO host ,while at higher doping level of x 〉 0.03 Mn2O3-like impurity phase is formed .Magnetization measurements indicate that the saturation magnetic moment of Ni1 - xMnxO film increases from 0.3 to 0.45 μB/Mn as the Mn content rises from 0.01 to 0.03 .It is proposed that interactions between Mn^3＋ ions mediated by Ni vacancies exhibit ferromagnetic coupling ,while interactions between Mn^2＋ ions exhibit antiferromagnetic coupling through superexchange interaction .

关 键 词：MN掺杂 NiO XAFS 室温铁磁性 

分 类 号：X131.2[环境科学与工程—环境科学] O614.241[理学—无机化学]