基于异向磁阻的三维磁场探测方法

三维磁场传感器,是用来测量空间磁场的一种装置,在工业生产和科学研究的许多领域都涉及到磁场测量的问题,如磁探矿、地质勘探、磁性材料研究、磁导航、同位素分离、电子束加工装置、受控热核反应以及人造地球卫星等。在很多地方,磁场检测的精确度跟检测范围显得尤为重要,对空间磁场的测量,也是现代科技所要求的发展方向。在高度智能化,微控制器被广泛应用的今天,利用磁阻器件,传感器芯片和单片机实现集成化,智能化成为改善空间磁场测量的比较有效的方法。

基于地磁感应的矿用机车位置检测传感器的研究

针对采用RFID等方法不能精确检测胶轮车位置的问题,提出了一种基于地磁感应的矿用机车位置检测传感器的设计方案,分析了地磁感应的检测原理,详细介绍了矿用机车位置检测传感器的硬件及软件设计。实际应用表明,该传感器不但适合无轨胶轮车的位置检测,也适合轨道电机车的位置检测。

Frustrated ferromagnetic transition in AB-stacked honeycomb bilayer

In two-dimensional(2D) ferromagnets, anisotropy is essential for the magnetic ordering as dictated by the Mermin-Wagner theorem. But when competing anisotropies are present, the phase transition becomes nontrivial. Here, utilizing highly sensitive susceptometry of scanning superconducting quantum interference device microscopy, we probe the spin correlations of ABC-stacked Cr Br3under zero magnetic field. We identify a plateau feature in susceptibility above the critical temperature(TC) in thick samples.It signifies a crossover regime induced by the competition between easy-plane intralayer exchange anisotropy versus uniaxial interlayer anisotropy. The evolution of the critical behavior from the bulk to 2D shows that the competition between the anisotropies is magnified in the reduced dimension. It leads to a strongly frustrated ferromagnetic transition in the bilayer with fluctuation on the order of TC, which is distinct from both the monolayer and the bulk. Our observation demonstrates unconventional 2D critical behavior on a honeycomb lattice.

Large and anisotropic linear magnetoresistance in bulk stoichiometric Cd_3As_2 crystals

Cd3As2 was recently identified as a novel three-dimensional （3D） topological semimetal hosting the long-pursuing 3D Dirac Fermion. Crystals of Cd3As2 grown preferentially along the [100] and [112] directions were obtained through the modified chemical vapor transfer growth method, thus allowing the examination of transport anisotropy. The resistivity and magnetore- sistance （MR） are basically linear with respect to magnetic field （H） in the measured temperature range of 2-300 K irrespective of the directions. The linear resistivity and MR are significantly anisotropic not only along [100] and [112] directions but also with respect to tilt angle between the growth directions and H, thus providing transport signatures of the 3D Dirac Fermion as well as the possible linear and anisotropic change of Weyl Fermi surface in H. Very large MR along the [100] direction is observed, even approaching 3100% at 2 K and 14 kOe （10e = 79.5775 A m^-l）. The results would be helpful in renewing interest in studying emergent phenomena arising from bulk 3D Dirac Fermion as well as in paving the way for Cd3As2 to be used in magnetoelectronic sensors.

Research Progress on Colossal Anisotropic Magnetoresistive Effect

Perovskite manganites show exotic functionalities due to the coupling between spin, charge, orbital and lattice, such as metal-insulator transition, colossal magnetoresistance （ CMR ） , charge-orbital order and phase separation. Recently, an extraordinary anisotropic magnetoresistance （ AMR ） has been observed in perovskite manganite single crystals. The AMR value is about 2 orders larger than that of the conventional 3E transition metals and alloys, which is attributed to tunable metal-insulator transition temperature modulated by the magnetic field. This result provides a new route for exploring novel AMR materials and their applications.