排序方式: 共有19条查询结果,搜索用时 15 毫秒
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利用傅里叶分析法测量光相位延迟器延迟量 总被引:3,自引:1,他引:2
为了精确测量光相位器的延迟量,提出了一种新的测量方法,并利用米勒矩阵理论分析了影响测量结果的因素。测量系统主要由起偏棱镜、标准四分之一波片、检偏棱镜、锁相放大器和微处理器构成。该方法利用最小二乘算法得到了最优傅里叶系数,利用锁相放大器的窄带滤波作用提高了信噪比,利用反馈环控制系统对步进电机的步进角进行了控制。误差分析表明这一方法的绝对误差小于0.29°,对四分之一石英波片相位延迟量进行了实验测试,结果表明其重复测量误差小于0.40°。 相似文献
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利用二次量子化方法研究了由相同面心立方结构(100)材料构成的铁磁性双层薄膜,重点讨论了铁磁性界面交换作用(JAB>0)和反铁磁性界面交换作用(JAB<0)对体系二维布里渊区能带结构的影响.结果表明,当界面交换作用大于体交换作用时,在体模上方出现光学型界面模;当界面交换作用小于体交换作用时,在体模下方出现声学型界面模.特别的是,当铁磁性界面交换作用大小在零与体交换作用之间时,在面心立方结构中同样能出现声学型界面模,这与简立方结构有明显区别.并且讨论了不同界面交换作用时宇称对界面模的影响. 相似文献
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The eigenproblems of spin waves in a symmetrical
ferromagnetic bilayered system with periodic boundary conditions are
solved using the interface-rescaling approach (IRA). The results
show that interface coupling between two sublayers would not
change the excitation energy of odd bulk modes, but change
excitation energy of even bulk modes. We call this peculiar
phenomenon the phenomenon of even bulk mode variance (PEBMV).
There are two kinds of mechanisms which cause PEBMV:
phase reversal and phase translation of the magnon at the
interface, corresponding, respectively, to the antiferromagnetic and
ferromagnetic interface coupling cases. PEBMV embodies the selective
effect of the interface on different bulk magnons. 相似文献
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High-spin states of ^160Tm are studied by the ^146 Nd(^19F, 5n) reaction at a beam energy of 102 MeV. The previously known πh11/2 + vi13/2 yrast band and πh11/2 + vh9/2 side band are confirmed. The level scheme is enriched and more low-lying levels are observed. A new side band is observed and assigned as the favoured signature partner of πd3/2 + vi13/2. The spin of this band is assigned with the energy level systematics. It is pointed out that the B (M1)/B (E2) ratios increase rapidly at the high frequency approaching the second crossing in the π h11/2 + vi13/2 braid, which is closely related to the alignment gain of the aligned i13/2 quasineutron. 相似文献
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合成了一系列Ni50-xCoxMn39Sn11 (8≤x≤10) 样品, 并对它们的结构和磁性进行了研究. 发现随Co含量的增加, 样品的饱和磁化强度逐渐增强, 并在Ni42Co8Mn39Sn11中实现了磁场诱发马氏体相变. 另外, 在Co大于8.0的成分中探测到了超自旋玻璃, 并且观察到交换偏置现象. 证实了超自旋玻璃的马氏体相和铁磁奥氏体母相共存, 这也是产生交换偏置的原因.我们猜测超自旋玻璃的形成可能是来源于Mn-Mn团簇的存在, 这和之前报道的Mn2Ni1.6Sn0.4 的结果相一致[1].
关键词:
NiCoMnSn
Heusler合金
超自旋玻璃
交换偏置 相似文献