Magnetic megabits

Improvements in recording densities that are allowing magnetic storage to pack more data than its optical counterparts are examined. The technologies that have driven the advances are discussed. They consist of highly sensitive magnetoresistive heads, ultra-low-noise magnetic media, and advanced signal detection techniques. Disk and tape performances are compared     

Analysis and improvements of accurate dynamic current mirrors

The possibility of realizing highly accurate dynamic current mirrors based on dynamic analog techniques and improvements thereof is considered. These current mirrors, which memorize the input current, are insensitive to transistor mismatch, whereas for conventional current mirrors, the accuracy is limited by the achievable matching. Different current mirror structures are presented, the interfacing parameters are shown, and their influence is explained. The dominant transients occurring during switching are shown. Improvements which allow for increases in the performance of dynamic current mirrors are proposed, and experimental results are shown     

Design of Spin-Torque Transfer Magnetoresistive RAM and CAM/TCAM with High Sensing and Search Speed

With a great scalability potential, nonvolatile magnetoresistive memory with spin-torque transfer (STT) programming has become a topic of great current interest. This paper addresses cell structure design for STT magnetoresistive RAM, content addressable memory (CAM) and ternary CAM (TCAM). We propose a new RAM cell structure design that can realize high speed and reliable sensing operations in the presence of relatively poor magnetoresistive ratio, while maintaining low sensing current through magnetic tunneling junctions (MTJs). We further apply the same basic design principle to develop new cell structures for nonvolatile CAM, and TCAM. The effectiveness of the proposed RAM, CAM and TCAM cell structures has been demonstrated by circuit simulation at 0.18 $ mu$m CMOS technology.      

一种新的自旋量子效应——电流感应磁化翻转

电流感应的磁化翻转效应是近年来继巨磁阻效应(GMR)和隧道磁阻效应(TMR)之后提出的一种nm尺度下新的自旋相关效应,在无外加磁场的情况下,垂直于铁磁层平面的自旋极化电流就能引起铁磁层的磁化翻转。该效应有望被用于制作新型的电流操纵磁存储器件。报道了该效应的理论和实验的研究进展。     

Wireless magnetoresistive microsystem for magnetic field measurements

The design and technology of magnetic semiconductor elements of wireless magnetoresistive microsystems for magnetic field measurements are proposed and the results of the investigations of a highly sensitivity magnetoresistive converter with magnetic field concentrators are presented. The characteristics of the developed measuring amplifier for operation with a signal from a low-resistance magnetoresistive bridge with a certain unbalance value are reported. The technology for fabricating magnetic semiconductor ICs based on thin-film magnetoresistive structures is described.     

Anisotropic and giant magnetoresistive elements

The technology of magnetoresistive element (MRE) fabrication and integration as well as some experimental results on the performance of anisotropic and giant magnetoresistive elements are discussed. Most emphasis is put on isolated MREs in specially designed test structures, although results on completed heads will also be discussed. Aspects such as output signal level, noise level, distortion and magnetic stability are the performance indicators considered.     

Development of magnetic semiconductor microsystems technology

The results of the development of technologies of magnetic semiconductor chips based on thinfilm magnetoresistive multilayer structures are presented. A brief overview of the main achievements in the field of magnetometric devices based on anisotropic and giant magnetoresistive effects is made.     

Magnetic Field Converters Based on the Spin-Tunnel Magnetic Resistance Effect

Russian Microelectronics - The modern designs of magnetic field transducers (MFTs) based on nanostructures with the spin-tunnel magnetoresistive effect (STMR) and the main areas of their...     

An automated stand for express-diagnostics of magnetoresistive structures

The design of an automated measuring stand for express-diagnostics of magnetoresistive structures are presented. This computer-controlled stand allows measurements of the magnetoresistances of film structures with high accuracy in a low alternating magnetic field. The stand has been tested on single- and multiple-layer magnetoresistive structures.     

基于GMR及TMR效应的磁随机存储器的最新应用开发

介绍了巨磁电阻（GMR）及隧道磁电阻（TMR）效应,讨论了计算机磁随机存储器（MRAM）的最新应用开发。     

Magnetic-field-dependent microwave absorption in HgSe in weak magnetic fields

The low-temperature magnetoresistive effect in the semiconductor HgSe:Fe in weak magnetic fields at microwave frequencies is examined. The negative and positive components of magnetoabsorption based on the magnetoresistive effect in the degenerate conduction band are analyzed. The special features of experiments carried out in the investigated frequency range are noted. The momentum and electron-energy relaxation times are determined from the experimental field and temperature dependences.     

基于轨迹图磁阻传感器车辆检测算法

采用磁阻传感器实现车辆车位占用状态的可靠、快速检测,至今没有得到很好地解决,单纯依靠阈值判断或者采用状态机检测的算法很难解决这一问题。现分析了当前的车辆检测算法,着重讨论传感器在车辆经过时输出曲线的特性。结合磁阻传感器的输出特性提出基于轨迹图分析的磁阻传感器车辆检测算法,该算法能很好的跟踪曲线特性并有利于信号曲线的处理。Matlab仿真证明了该算法的可行性和正确性。     

A silicon diode array scan converter for high-speed transient recording

A double-ended scan converter tube has recently been developed which uses a silicon diode array for the storage target. The purpose of the device is to capture high-speed single transients or low-repetition-rate signals and to retain the information until it can be read out at speeds slow enough for handling by conventional processing and display circuits. Improvements in wide-bandwidth deflection and the resolution of both writing and reading guns, combined with a charge gain of 2000 in the target, enables data to be stored at unprecedented rates. Information writing speeds of 2 × 10¹²tracewidths/s are possible with the device, sufficient for displaying a full-screen 2-GHz Sine wave. To reliably digitize the readout for signal processing, a signal-to-noise ratio of about 20:1 is required which the device, will provide at speeds up to 5 × 10¹¹tracewidths/s. Resolution at a 50-percent modulation level is 400 TV lines per horizontal scan (15.7 cycles/mm at the target).     

The gaussistor, a solid state electronic valve

The property of magnetoresistivity can be employed to produce tuned amplifiers and oscillators principally for the sub-audio and possibly for the audio range. To accomplish this, a strip or a coil of a magnetoresistive material, such as bismuth, is placed in the magnetic circuit of a laminated or a ferrite core of an inductor and appropriately wired into an electric circuit containing a dc power supply. The circuitry is simple and the device can be constructed to match a wide range of input and output impedances. The recently developed semiconductor indium antimonide, having an exceptionally high magnetoresistive coefficient, offers hope of obtaining useful power gain at room temperature. The basic theoretical concepts are presented and experimental results with bismuth and indium antimonide are given.     

A New Hand-Held Microsystem Architecture for Biological Analysis

This paper presents a hand-held microsystem based on new fully integrated magnetoresistive biochips for biomolecular recognition (DNA hybridization, antibody antigen interaction, etc.). Magnetoresistive chip surfaces are chemically treated, enabling the immobilization of probe biomolecules such as DNA or antibodies. Fluid handling is also integrated in the biochip. The proposed microsystem not only integrates the biochip, which is an array of 16times16 magnetoresistive sensors, but it also provides all the electronic circuitry for addressing and reading out each transducer. The proposed architecture and circuits were specifically designed for achieving a compact, programmable and portable microsystem. The microsystem also integrates a hand-held analyzer connected through a wireless channel. A prototype of the system was already developed and detection of magnetic nanoparticles was obtained. This indicates that the system may be used for magnetic label based bioassays     

Thin-film multilayer magnetic sensors based on the anisotropic magnetoresistive effect

The design and operation of thin-film multilayer sensors based on the anisotropic magnetoresistive effect are considered from the theoretical and experimental viewpoints.     

Single-event multiple transients in guard-ring hardened inverter chains of different layout designs

Single-event multiple transients (SEMTs) measurement based on an on-chip self-triggered method is performed. Measurement results for guard-ring hardened inverter chains of two layout designs, including a source/drain sharing design and a conventional design, are compared under pulsed laser irradiation. Pulsed laser exposures with different energies show that the guard-ring hardened inverter chain with a source/drain sharing design is more sensitive to single-event double transients (SEDTs). It is found that SEDTs with small temporal differences can be merged into single-event single transients (SESTs) thanks to the pulse broadening effect. A layout-hardened design for SEDTs in the guard-ring hardened inverter chain is also suggested.     

Microwave hall field inertia due to dielectric relaxation time

The magnetoresistive e.m.f. caused by microwave was measured as a function ofωτ _m in wide (3 cm – 4mm) range wave length. It has been found that Maxwell relaxation time does not influence the microwave Hall field lag in semiconductors. The discussion of these results is presented.     

Transient RF signals during the switching of MESFET control devices

An analytical model that predicts the intrinsic small-signal switching transients for MESFET control devices is developed. Theoretical results for video-breakthrough and small-signal RF switching waveforms are in excellent agreement with measurements on many devices. Although the intrinsic transients are less than a few nanoseconds in duration, FET material aspects (such as surface states) can induce much longer transients. The 10-90% switching time, which is dominated by intrinsic effects, can be lowered by reducing gate length and gate bias resistance (the latter is more feasible with recently reported diode-gate FFTs)     

A review of magnetic sensors

Eleven of the most common technologies used for magnetic field sensing are described and compared. These are the search coil, flux-gate, optically pumped, nuclear precession, SQUID, Hall-effect, magnetoresistive, magnetodiode, magnetotransistor, fiber optic, and magnetooptic technologies. The use of these sensors in relation to working with or around the Earth's magnetic field is addressed. Three classes of applications and a specific application from each are examined: low-sensitivity (noncontact switching), medium-sensitivity (magnetic anomaly detection and magnetic compassing), and high-sensitivity (brain-function mapping)