Growth and Magnetic Properties of Zincblende CrSb Epilayers on Relaxed and Strained （In, Ga）As Buffers

Zincblende CrSb （zb-CrSb） layers with room-temperature ferromagnetism have been grown on relaxed and strained （In,Ga）As buffer layers epitaxially prepared on （001） GaAs substrates by molecular-beam epitaxy. The structural characterizations of CrSb layers fabricated under the two cases are studied by using synchrotron grazing incidence x-ray diffraction （GID）. The results of GID experiments indicate that no sign of second phase exists in all the zb-CrSb layers. Superconducting quantum interference device measurements demonstrate that the thickness of zb-CrSb layers grown on both relaxed and strained （In,Ga）As buffer layers can be increased to ～12 monolayers （～3.6nm）, compared to ,～3 monolayers （～1 nm） on GaAs directly.     

80Rb的旋称劈裂反转及负宇称带的回弯

通过熔合蒸发反应⁶⁵Cu+¹⁹F,⁶⁶Zn+¹⁸O及⁶⁸Zn+¹⁶O,在3种入射束流的能量分别为75MeV,76MeV及80MeV研究了⁸⁰Rb高自旋态的能级结构.增加了20多条新的γ跃迁,在已知负宇称转晕带上建立了两条新的边带.将原有的第二条负宇称带的自旋态从12^－推高到了22^－,并首次观察到这个带的回弯,它的回弯频率为0.49MeV;负宇称转晕带在15^－时出现了旋称反转,第二负宇称带存在明显的旋称劈裂,但没有观察到旋称反转,这两条负宇称带的结构均与其同中子数核⁸²Y非常相似.     

Negative Parity Bands and Signature Splitting Inversion in ^80Rb

High spin states in ^80Rb were studied via the ^65Cu ^19F, ^66Zn ^180 and ^68Zn ^160 reactions. The 75-MeV ^19F,76-MeV ^180 and 80-MeV ^160 beams were provided by the CIAE HI-13 Tandem accelerator and the JAERI Tandem accelerator. The prompt γ-γ coincidence and the directional correlation from oriented nuclei (DCO)were measured by the detector arrays in CIAE and JAERI. Twenty-three new states with 28 new transitionshave been assigned to ^80Rb. The states were observed up to spins of 20^ and 22^- in the α= 0 branch for thepositive and negative parity yrast bands respectively. The negative parity non-yrast bands were significantlyextended up to spins of 22^- and 15^-. The band crossings with frequencies 0.51 MeV and 0.61 MeV in the α= 0cascade were observed for the first time. The signature splitting was observed in both negative parity bands. Thesignature inversions at spins of about 7h and 15h were observed.     

106Ag手征性实验研究

利用能量为60MeV的¹¹B束流, 通过¹⁰⁰Mo(¹¹B, 5n)¹⁰⁶Ag熔合蒸发反应布居¹⁰⁶Ag的高自旋态, 用15台带BGO反康的HPGe探测器进行在束γ谱学测量. 通过γ-γ符合矩阵开窗分析和DCO比值分析, 建立了¹⁰⁶Ag新的能级纲图, 观测到26条新γ跃迁. 与相邻同位素奇奇核¹⁰⁴Rh比较, ¹⁰⁶}Ag中带1和带2具有A≈100区手征二重带的3个特征, 推测它们可能是基于πg_9/2⊙υh_11/2组态的手征二重带. 但它们的角动量顺排不一致, 在实验上还需进一步的测量研究.     

双奇核140Pr的高自旋态能级纲图

通过¹³⁰Te(¹⁴N,4n)反应首次对双奇核¹⁴⁰Pr进行了在束γ谱学研究.在实验中进行了γ射线的激发函数、γ射线单谱和γγt符合测量.建立了激发能达4717.3keV的¹⁴⁰Pr的能级纲图,其中包括新发现的42条γ射线和新建立的27个能级.基于实验测量的γ跃迁各向异性度,建议了¹⁴⁰Pr部分能级的自旋值.根据¹⁴⁰Pr附近同位素核结构的系统性,对部分能级的准粒子组态作了定性的讨论.     

核矩测量和核结构研究

简要介绍时间微分扰动角分布、瞬态场-离子注入扰动角分布、β-放射性探测的核磁共振和核电共振等原子核核矩测量方法及其在核结构研究中的应用, 给出了⁴³Sc(19/2^－,3.1232MeV,0.45μs)同质异能态、^84、86Zr和⁸³Y高自旋态、¹⁷F(I=5/2⁺,T_1/2=64.49s)、¹²B和¹²N镜核对的核矩测量和核结构研究例子.     

155Tm核的能级结构

通过重离子熔合蒸发反应¹⁴²Nd(¹⁹F, 6n)¹⁵⁵Tm来布居¹⁵⁵Tm核的高自旋态. 发现了一些新的γ跃迁, 经过γ-γ符合分析, 建立了新的能级纲图. 利用系统学比较对新建立的¹⁵⁵Tm能级进行了讨论.     

Dipole bands in nucleus ^139Pm

High-spin states in nucleus ^139Pm have been studied using the reaction ^116Cd（^27Al, 4n）^139Pm. Two dipole cascades have been found. Spin and parity assignments were based on the Directional Correlation of Oriented Nuclei （DCO） ratios and systematic behavior in neighboring odd-proton nuclei. The level structures of ^139Pm are compared with those of the N = 78 isotone ^141Eu in which two dipole bands have been confirmed as magnetic rotational bands. The close similarity between them suggests that the dipole bands in ^139Pm may be magnetic rotational bands.     

双奇核170Re高自旋态实验研究

在166MeV的束流能量下,利用重离子熔合蒸发反应142Nd(32S, 1p3nγ) 170Re布居了170Re的高自旋激发态. 用12套带BGO反康普顿抑制的高纯锗探测器阵列进行了在束X-γ和γ-γ符合测量. 基于对实验测量结果及周围邻近核已知信息的综合分析,首次建立了双奇核170Re的转动带能级纲图. 根据实验提取出的准粒子顺排、旋称劈裂等结构特征和Re双奇核同位素带结构系统学知识的比较分析,指出该带的准粒子组态是πh11/2(○×)υi13/2.     

90Nb和91Nb的高自旋态结构

用能量为80MeV的¹⁹F束通过反应⁷⁶Ge(¹⁹F,xn)布居了⁹⁰Nb和⁹¹Nb的高自旋态. 通过在束测量分析⁹⁰Nb和⁹¹Nb退激射线的符合级联关系, 发现了新的属于⁹⁰Nb和⁹¹Nb$的跃迁, 建立了⁹⁰Nb和⁹¹Nb$的高自旋态能级纲图. 通过经验壳模型计算指定了部分能级的组态, 并结合实验DCO比值和与相邻核素的系统比较, 确认了新能级的自旋和宇称.