Theoretical analysis of the anisotropy of the magnetization of the Ho^3＋ ion in holmium iron garnet single crystals

The spontaneous magnetization of the Ho^3＋ ion in holmium iron garnet （HoIG） single crystals in the temperature range of 4.2-294K along the directions [111], [110], and [100] are calculated, taking into account the effects of six magnetically inequivalent sites occupied by the Ho^3＋ ions based on the quantum theory. The calculated results show that the magnetization of the Ho^3＋ ion in HoIG is obviously anisotropic. The theoretical results ave in agreement with those of experiments. A primary interpretation of the anisotropy of magnetization of the Ho^3＋ ion in HoIG is put forward.     

近红外传感器在汽车改造技术中的应用研究

利用反射式近红外传感器及语音录放组件,研究了汽车倒车防撞语音提示器。当汽车倒车时,只要距车身后尾一定的距离内有人或物体存在,就会有一部分红外光信号经人或物体反射回来,被与发射管同排安装的光敏接收管收到并转换成同频率的电信号后,由模块内部电路进行放大、解调、整形、比较处理后,在输出端输出控制信号,控制语音录放组件工作,告诉司机车后有人、车后有物体。由于近红外线传感器、语音录放组件均为一体化结构,成本低、接线简单、抗震能力强、测量准确、工作稳定可靠,适合在汽车上安装使用。     

CexY3—xAl5O12中Ce^3＋的4f多重态耦合对其磁矩和磁光性能的影响

计算了ＣｅｘＹ３－ｘＡｌ５Ｏ２晶体中Ｃｅ＾３＋由晶场导致的４ｆ欧重态之间的耦合对Ｃｅ＾３＋离子基态磁矩和磁光Ｆａｒａｄａｙ旋转的影响及其温度特性。结果表明，Ｃｅ＾３＋４ｆ＾２Ｆ７／２和＾２Ｆ５／２多重态的耦合，使Ｃｅ＾３＋的基态磁和左在温度３００Ｋ和２０Ｋ时分别     

热释电红外探测器在安全防护系统中的应用研究

利用人体发出的红外线,通过热释电红外传感器的接收和放大,形成具有一定电压幅度的控制信号,用这一控制信号去触发语音录放电路工作,就可制成具有自动控制功能的热释电红外探测语音录放系统。电路采用最新热释电红外探测模块与语音录放模块设计,当有人出现在热释电红外探测模块的探测范围时,热释电红外传感器首先将接收到的红外辐射能转换成电能信号,再经内部电路放大、比较处理后输出控制信号,触发语音录放模块工作,播放事先录制好的语音内容,提醒人们注意。该系统电路简洁、成本低、抗干扰能力强、耐低温、免调试、工作稳定和使用方便。适宜于安装在变电所、高压开关柜和电力变压器等危及人身安全的处所使用。     

THE INFLUENCE OF THE ADMIXING OF DIFFERENT MULTIPLETS ON THE SPIN MAGNETIC MOMENT AND FARADAY EFFECT OF HARE EARTH IONS IN GARNETS

The influence of the admixing of the excited multiplets of the ground configuration with the ground multiplet on the spin magnetic moment of the crystal- field-and exchange-interaction-split ground state, the Faraday rotation and the magneto-optic coefficient induced by the rare earth ions in rare-earth-substituted garnets Y_3-xR_xFe₅O₁₂ (R=Ce and Pr) has been calculated in this paper. It is found that, in the case of Ce³⁺ ions, the admixing of the 4f^{1 2}F_7/2 multiplet with the ²F_5/2 multiplet makes the spin magnetic moment of the crystal-field- and exchange-interaction-split ground state increase by 140% and the Faraday rotation increase by 180% at 633nm wavelength, and 150% at 1150nm at 294 K. In the case of Pr³⁺ ions, the admixing of the 4f^{2 3}H₅ multiplet with the ³H₄ multiplet makes the spin magnetic moment of the crystal-field- and exchange-interaction-split ground state increase by 34% and the Faraday rotation increase by 59% at 294K. The admixing of different multiplets of the Ce³⁺ ions makes the ratio between the magneto-optic coefficients at 50 and 294K increase by 7% at 633nm wavelength and 15% at 1150nm.     

Ce∶YIG自旋轨道耦合对磁光效应的影响

计算了Ce∶YIG中Ce3+离子自旋轨道耦合对磁光效应的影响,计算结果表明,Ce3+离子基态的自旋轨道耦合对磁光效应有很大影响,Faraday旋转与λf(基态的自旋轨道耦合系数与其正常值的比值)不是线性关系,在λf约为03时,Faraday旋转有明显的峰值,激发态的自旋轨道耦合对磁光效应影响很小. 关键词：