La-Ni系列合金纳米管（线）的磁光性能研究

发布时间：2018-02-28 04:13

  本文关键词： 合金纳米线或管 电化学沉积 阳极氧化铝模板(AAO) 磁各向异性 荧光强度　出处：《内蒙古大学》2015年硕士论文　论文类型：学位论文

【摘要】：稀土元素特有的4f电子层结构,赋予它有别于其他元素的物理、化学性质,在科研领域中倍受人们的重视。本文用电化学沉积法在孔洞均匀的氧化铝模板内组装La-Ni纳米线、纳米管和La-Ni:Sm纳米线列阵。实验中用到的测量仪器：扫描电子显微镜、透射电子显微镜和X射线衍射仪对样品的形貌和晶体内部结构进行扫描；用X射线能量色散仪对样品成分比例进行粗略测试；测量样品的磁性能时使用振动样品磁强计；用荧光光度计(FLS920)测量发光材料的荧光性能。实验中我们采用不同孔径的AAO模板组装成了La-Ni纳米线、纳米管列阵。XRD图和选区电子衍射图SEAD表明La-Ni合金纳米线和纳米管的晶体结构是非晶。磁性测量结果说明La-Ni合金纳米线和纳米管都有很强的磁各向异性能,其中形状各向异性起主要决定作用,并且诱导易磁化轴平行于纳米线、管的长轴。将La-Ni合金纳米管在氮气的保护下进行退火,其磁性能发生了转变,磁各向异性从形状各向异性起主导作用转变为静磁相互作用起主导作用,且易磁化轴从平行于纳米管的长轴转变为垂直于纳米管的长轴,而磁晶各向异性几乎不变。同样用不同孔径的AAO模板制备了La-Ni:Sm纳米线列阵。在未掺杂Sm3+时,La-Ni合金纳米线列阵出现了发光现象,是由于Ni电子的能级跃迁产生的。掺杂Sm3+时,La-Ni合金纳米线出现了Sm3+的特征峰,即激发峰波长为342 nm、360 nm、370 nm、408 nm、432 nm和470 nm,发生了6H5/2→4K17/2、6H5/2→4D3/2、 6H5/2→6P7/2、6H5/2→4K11/2、6H5/2→4M19/2和6H5/2→4I13/2的能级跃迁；发射峰波长为572 nm、603 nm和643 nm,对应于Sm3+的4G5/2→6H7/2、4G5/2→6H7/2、 465/2→6H9/2的能级跃迁。掺杂不同比例8m3+时,La-Ni:Sm合金纳米线列阵在掺杂比例为3：100时荧光强度值最大,之后出现了浓度淬灭现象。掺杂相同比例的Sm3+时,不同温度下La-Ni:Sm合金纳米线列阵的荧光强度出现先增加后减小的现象,在T=400℃时,荧光强度值最大；不同直径的La-Ni:Sm合金纳米线列阵的荧光强度随直径的增加,出现先增加后减小的现象,在D=100 nm时,荧光强度值最大。
[Abstract]:The unique 4f electron layer structure of rare earth elements, which gives it physical and chemical properties different from other elements, has attracted much attention in the field of scientific research. In this paper, La-Ni nanowires have been assembled by electrochemical deposition in homogeneous alumina templates. Nanotubes and La-Ni:Sm nanowires. Measuring instruments used in the experiment: scanning electron microscope, transmission electron microscope and X-ray diffractometer to scan the morphology and crystal structure of the sample; The composition ratio of the sample was roughly measured by X-ray energy dispersive instrument, and the vibrating sample magnetometer was used to measure the magnetic properties of the sample. Fluorescence properties of luminescent materials were measured by fluorescence photometer FLS920. In the experiment, La-Ni nanowires were assembled by using AAO templates with different pore sizes. The crystal structure of La-Ni alloy nanowires and nanotubes is amorphous, and the magnetic measurements show that both La-Ni alloy nanowires and nanotubes have strong magnetic anisotropy. The shape anisotropy plays an important role and induces the easy magnetization axis to be parallel to the long axis of the nanowires and tubes. The magnetic properties of the La-Ni alloy nanotubes annealed under the protection of nitrogen have been transformed. The magnetic anisotropy changes from shape anisotropy to magnetostatic interaction, and the magnetization axis changes from the long axis parallel to the nanotube to the long axis perpendicular to the nanotube. The magnetocrystalline anisotropy is almost unchanged. La-Ni:Sm nanowires are also prepared by using AAO templates with different pore sizes. The luminescent phenomena of La Ni alloy nanowires are observed when the nanowires are not doped with Sm3. Sm3 doped La Ni alloy nanowires exhibit the characteristic peak of Sm3, that is, the wavelength of excitation peak is 342 nm ~ 360nm ~ 360nm ~ 370nm ~ (-1) ~ 408nm ~ (2) nm ~ (432 nm), and 6H _ 5r ~ (2) _ 2 occurs. 鈫，

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