Co、Ni共掺杂TiO_2纳米颗粒的制备及室温铁磁性

Preparation and Room-temperature Ferromagnetism of Co,Ni-doped TiO_2 Nanobelts

利用溶胶-凝胶法制备钴、镍共掺杂TiO_2纳米颗粒。实验中陈化、退火时间以及退火温度和掺杂物总量(4 mol%)保持不变,通过改变掺杂物,使掺杂物质不同(4 mol%Co,2 mol%Co+2mol%Ni,4mol%Ni),对制备的纳米晶体结构和磁性进行分析,探究掺杂物对结构和磁性的影响。形貌结构通过X射线衍射(XRD)和透射电子显微镜(TEM)进行表征。结果表明,TiO_2纳米颗粒成功掺杂,颗粒大小稍有变化,结构无变化。磁滞回线由VSM磁强计进行表征。结果显示,Co掺杂TiO_2纳米颗粒磁性最强,TiO_2晶格中Ti元素为+4价;由于掺入Co^(2+)比Ni^(3+)产生的氧空位要多,导致Ti_(1-x)Co_xO_2室温铁磁性更强;当同时掺入Co^(2+)和Ni^(3+),Ti_(1-x-y)Co_xNi_yO_2没有室温铁磁性,可能是Co^(2+)和Ni^(3+)互补作用降低氧空位浓度造成的。

In this paper,Co, Ni-doped TiO2 Nanobelts is prepared by sol-gel method. In the experiment,the retrogradation,annealing time and annealing temperature and dopant amount（4 mol %） remains the same, the prepared nanometer crystal structure and magnetic properties is analyzed with the dopant being changed （4 mol% Co,2 mol% Co＋ 2 mol% Ni,4 mol% Ni and the influence of dopants on structure and magnetic is discussed. In this paper, morphology structure is characterized by X-ray diffraction（XRD） and transmission electron mieroscopy（TEM）. The result shows that, the successfully doped TiO2 Nanobelts have a slight change in its size but have no change in structure. Hysteresis loop is characterized by VSM magnetometer and the results shows that Co-doped TiO2 Nanobelts have the strongest magnetism and the valence of Ti element is ＋4 within TiO2. Ti-x CoxO2 has a stronger Room-temperature Ferromagnetism be- cause the doped Co2＋ has more oxygen vacancy than he doped Ni3＋. When Co2＋ and Ni3＋ are doped togeth- er, Ti1-xCoxO2 has no Room-temperature Ferromagnetism, probably because the oxygen vacancy concentra- tion is reduced by the eomplementation action of Co2＋ and Ni3＋.