In this paper,the structural and magnetic properties of Ni metal implanted TiO 2 single crystals are discussed.Ni nanocrystals (NCs) have been formed in TiO 2 after ion implantation.Their crystalline sizes were increased with increasing post-annealing temperature.Metallic Ni NCs inside the TiO 2 matrix are stable up to an annealing temperature of 1073 K.The Ni NCs forming inside TiO 2 are the major contribution of the measured ferromagnetism.
与传统的铁素体钢相比,氧化物弥散强化(ODS)的铁素体钢具有更优的耐高温和抗辐照性能,近年来成为先进核能装置重要的候选结构材料。在HIRFL的扇聚焦型回旋加速器(SFC)材料辐照终端,对一种氧化物弥散强化(ODS)铁素体钢MA956进行了高能Ne离子辐照实验,旨在研究级联碰撞损伤和惰性气体原子注入条件下该材料力学性能的变化。利用辐照终端的能量衰减装置将SFC出口123.4 Me V的离子能量分解为介于38.5～121.0 Me V之间的30个入射能量值,并通过双面辐照在厚度60μm的样品中均匀产生了损伤。辐照剂量为9×1016ions/cm2,在样品中的平均位移损伤为0.7 dpa,注入的Ne原子浓度为350 appm。辐照期间样品温度保持在440℃附近。对辐照前后的样品分别在室温和500℃下进行了小冲杆试验(Small-punch Test),获得了辐照前后样品的加载位移曲线,由此得到该辐照条件下样品的延性损失为18%～26%。通过扫描电子显微镜观察了断口形貌和厚度变化,估算了样品的等效断裂应变和断裂韧性。结果表明,MA956钢经过高能Ne离子辐照后等延伸率减小,断裂韧性降低,样品发生了一定的脆化。透射电镜结果说明氧化物弥散相界面处微空洞的形成可能是导致脆化的原因。
A 240-nm thick Al0.4In0.02Ga0.58N layer is grown by metal organic chemical vapour deposition, with an over 1-μm thick GaN layer used as a buffer layer on a substrate of sapphire （0001）. Rutherford backscattering and channeling are used to characterize the microstructure of AlInGaN. The results show a good crystalline quality of AIInGaN （χmin = 1.5%） with GaN buffer layer. The channeling angular scan around an off-normal {1213} axis in the {1010} plane of the AlInGaN layer is used to determine tetragonal distortion eT, which is caused by the elastic strain in the AIInGaN. The resulting AlInGaN is subjected to an elastic strain at interracial layer, and the strain decreases gradually towards the near-surface layer. It is expected that an epitaxial AlInGaN thin film with a thickness of 850 nm will be fully relaxed （^eT = 0）.
Fe ions of dose 8×10^16 cm^-2 are implanted into a ZnO single crystal at 180 keV. Annealing at 1073 K leads to the formation of zinc ferrite （ZnFe2O4）, which is verified by synchrotron radiation X-ray diffraction （SR-XRD） and X-ray photoelectron spectroscopy （XPS）. The crystallographically oriented ZnFe2O4 is formed inside the ZnO with the orientation relationship of ZnFe2O4 （111）//ZnO （0001）. Superconducting quantum interference device （SQUID） measurements show that the as-implanted and post-annealing samples are both ferromagnetic at 5 K. The synthesized ZnFe2O4 is superparamagnetic, with a blocking temperature （TB = 25 K）, indicated by zero field cooling and field cooling （ZFC/FC） measurements.
