高线电机参数优化及技术国产化的研究与应用

介绍了为降低新疆昆玉高线车间工程投资、确保项目工期,以国产电机替代进口电机的设想,通过技术人员的交流、考察、论证、优化设计,最终以国产上海电机厂生产的2台大电机替代了进口电机,实现了高线关键设备——两台高精度大电机的国产化,为今后同类设备的选型提供了可借鉴的经验,工程直接投资减少760万元,确保了项目按期投产。     

Magnetic Microstructures of 2:17 Type Sm(Co,Fe,Cu,Zr)z Magnets Detected by Magnetic Force Microscopy

The magnetic microstructures of 2:17 type Sm(Co,Fe,Cu,Zr)z magnets were detected by magnetic force microscopy.Comparing the microstructures of the specimens coated with and without Ta thin film before and after heat-treatment, it is found that: (a) as a protection layer, Ta coating layer about 20 nm thick can effectively restrain Sm volatilization under high temperature;(b) the stress built in the 2:17 type Sm-Co magnets during specimen preparation only affects some local parts of the domain structures;(c) the magnetic microstructures vary largely for specimens heat-treated at high temperature without Ta film coating due to Sm volatilization.In addition, by comparing with high coercivity Fe-Pt point tips, it is found that the Co-Cr thin-film tips are not suitable for detecting the magnetic microstructures of strong permanent magnets.     

Impulse plasma deposition of magnetic nanocomposite layers

The most characteristic feature of the IPD method is that the synthesis proceeds in the impulse plasma itself, with the participation of ions. The IPD growth mechanism, originating from clusters of constituent materials, makes this method particularly suitable for the fabrication of nanocomposite layers.The material synthesised in the present experiment was an Fe-Ti alloy. The sources of Fe and Ti were the internal electrodes of two independent impulse plasma accelerators operated in an alternate mode. It appeared that the Fe-Ti alloy forms at the interface between the Fe and Ti nanocrystals as a result of the surface diffusion due to the coalescence of the nanocrystals.     

High Security FeRAM‐Based EPC C1G2 UHF (860 MHz‐960 MHz) Passive RFID Tag Chip

The metal‐ferroelectric‐metal (MFM) capacitor in the ferroelectric random access memory (FeRAM) embedded RFID chip is used in both the memory cell region and the peripheral analog and digital circuit area for capacitance parameter control. The capacitance value of the MFM capacitor is about 30 times larger than that of conventional capacitors, such as the poly‐insulator‐poly (PIP) capacitor and the metal‐insulator‐metal (MIM) capacitor. An MFM capacitor directly stacked over the analog and memory circuit region can share the layout area with the circuit region; thus, the chip size can be reduced by about 60%. The energy transformation efficiency using the MFM scheme is higher than that of the PIP scheme in RFID chips. The radio frequency operational signal properties using circuits with MFM capacitors are almost the same as or better than with PIP, MIM, and MOS capacitors. For the default value specification requirement, the default set cell is designed with an additional dummy cell.     

Depletion effects at phase boundaries in 2205 duplex stainless steel characterized with SKPFM and TEM/EDS

2205 duplex stainless steel, which had undergone two different heat treatments, was characterized by means of SEM/EDS, TEM/EDS, magnetic force microscopy (MFM) and scanning Kelvin probe force microscopy (SKPFM). In general, paramagnetic austenite was found to exhibit the highest Volta potential, followed by non-magnetic sigma phase and ferromagnetic ferrite. The local Volta potential drop at the phase boundaries is clearly visible in the slowly cooled sample with sigma phase precipitate while it is not notable in the solution-annealed reference sample. Chemical composition line analyses with TEM/EDS showed the depletion of Cr and Mo at the phase boundaries.     

利用磁力显微镜观察铁镍合金丝的磁畴结构

本文介绍了磁力显微镜的起源和基本原理,以及应用状况。尝试了用磁力显微镜观察铁镍合金和铁镍合金丝的纵截面磁畴结构,并比较了退火前后合金丝的磁畴结构的变化。分析了拉拔应力以及退火对铁镍合金磁织构的影响。     

Comparison and Validation of Different Magnetic Force Microscopy Calibration Schemes

The future of consumer electronics depends on the capability to reliably fabricate nanostructures with given physical properties. Therefore, techniques to characterize materials and devices with nanoscale resolution are crucial. Among these is magnetic force microscopy (MFM), which transduces the magnetic force between the sample and a magnetic oscillating probe into a phase shift, enabling the locally resolved study of magnetic field patterns down to 10 nm. Here, the progress done toward making quantitative MFM a common tool in nanocharacterization laboratories is shown. The reliability and ease of use of the calibration method based on a magnetic reference sample, with a calculable stray field, and a deconvolution algorithm is demonstrated. This is achieved by comparing two calibration approaches combined with numerical modeling as a quantitative link: measuring the probe's effect on the voltage signal when scanning above a nanosized graphene Hall sensor, and recording the MFM phase shift signal when the probe scans across magnetic fields produced by metallic microcoils. Furthermore, in the case of the deconvolution algorithm, it is shown how it can be applied using the open‐source software package Gwyddion. The estimated magnetic dipole approximation for the most common probes currently in the market is also reported.     

Magnetoelectric coupling in CoFe2O4-Pb(Zr0.2Ti0.8)O3 coaxial nanofibers

In this work, we reported the fabrication and magnetoelectric coupling properties of the multiferroic CoFe₂O₄-PbZr_0.2Ti_0.8O₃ (CFO-PZT) coaxial nanofibers synthesized by electrospinning technique. The coaxial structure of nanofibers was demonstrated by magnetic force microscope and transmission electron microscope. The multiferroic properties of coaxial nanofibers have been revealed by magnetic hysteresis loops and piezoresponse amplitude butterfly curves and phase hysteresis loops. The as-prepared coaxial nanofibers show an effective piezoelectric coefficient d₃₃ of 30 pm/V and a saturated magnetization of 12 emu/g. Their magnetoelectric response has been probed by means of the localized changes in magnetization after poling the domains of the composite system. A static, large converse magnetoelectric coupling coefficient of 1.2 × 10⁻⁸ s/m was obtained in a single CFO-PZT nanofiber.     

Numerical simulation of MFM image of a magnetic nano-contact

A MFM image of a magnetic nano-contact is studied numerically. We show that the ring- or arc-shaped MFM images with diameter of the order of 100 nm appear while the size of a nano-contact is of the order of 1 nm. We also show that the origin of the ring or arc-shaped MFM image is the oscillation of the magnetization of a nano-contact induced by the interaction between the MFM-tip and the nano-contact.