Liu Huan, Li Gongping, E Dejun, Xu Nannan, Lin Qiaolu, Gao Xudong, Lan Changlin, Chen Jingsheng, Wang Canglong, Zhan Xuwen, Zhang Kai
School of Nuclear Science and Technology, Lanzhou University Lanzhou Gansu 730000 China
Institute of Modern Physics, Chinese Academy of Sciences Lanzhou Gansu 730000 China.
RSC Adv. 2020 May 18;10(32):18687-18693. doi: 10.1039/d0ra02220a. eCollection 2020 May 14.
Room temperature ferromagnetism (RTFM) was observed in unirradiated rutile TiO single crystals prepared by the floating zone method due to oxygen vacancy (V) defects. D-D neutrons mainly collide elastically with TiO, producing V, titanium vacancies (V) and other point defects; the density and kind of defect is related to the neutron irradiation fluence. D-D neutron irradiation is used to regulate the concentration and type of defect, avoiding impurity elements. As the irradiation fluence increases, the saturation magnetization (M) first increases, then decreases and then increases. To verify the origin of RTFM, the CASTEP module was used to calculate the magnetic and structural properties of point defects in TiO. V induces a 2.39 magnetic moment, Ti and F induce 1.28 and 1.70 magnetic moments, respectively, while V induces a magnetic moment of ∼4 . Combining experimental and theoretical results, increases in V concentration lead to M increases; more V combine with electrons to form F, inducing a smaller magnetic moment. V and V play a key role and M changes accordingly with larger fluence. V, F and V are the most likely origins of RTFM.
通过浮区法制备的未辐照金红石型TiO单晶中，由于氧空位（V）缺陷而观察到室温铁磁性（RTFM）。D-D中子主要与TiO发生弹性碰撞，产生V、钛空位（V）和其他点缺陷；缺陷的密度和种类与中子辐照通量有关。D-D中子辐照用于调节缺陷的浓度和类型，避免杂质元素。随着辐照通量的增加，饱和磁化强度（M）先增加，然后减小，再增加。为了验证RTFM的起源，使用CASTEP模块计算了TiO中点缺陷的磁性和结构性质。V诱导出2.39的磁矩，Ti和F分别诱导出1.28和1.70的磁矩，而V诱导出约4的磁矩。结合实验和理论结果，V浓度的增加导致M增加；更多的V与电子结合形成F，诱导出较小的磁矩。V和V起关键作用，随着通量的增加M相应变化。V、F和V是RTFM最可能的起源。
