Giant Magneto-Impedance Effect in Fe_(96-x)B_4 (x=7 or 10) Nanocrystalline Ribbons

The total ribbon voltage of as-quenched and annealed Fe96-xZr_xB_4 (x=7 or 10) ribbons has been measured as a function of applied dc field and drive current frequency. The experimental results show that both samples exist the optimum annealing temperature and optimum frequency at which the relative change in ribbon voltage is strongest, and the sensitivity of the magnetic response of the annealed Fe_89Zr_7B_4 ribbon is two order of magnitude larger than that of the annealed Fe_86Zr_10 B4 ribbon. The effect of magnetic properties and structural characteristics on giant magneto-impedance was discussed.

Giant Magneto-impedance Effect in Composite Wires with Different Core Layer

Composite structure materials were potential sensing elements for magnetic sensors due to Giant magnetoimpedance(GMI) effect. Two kinds of composite wires with different magnetic/non-magnetic structures were fabricated by using electroless deposition methods and the magnetoimpedance properties were investigated. The maximum GMI ratio of 114% was acquired at 60 MHz in the composite wires with a ferromagnetic core, whereas, 116% of maximum GMI ratio was found in the composite wires with a conductive core at low frequency of 600 k Hz. These results exhibit that the GMI ratio reaches the maximum when magnetoresistance ratio ?R/R and magnetoinductance ratio ?X/X make the comparative contributions to the total magnetoimpedance(MI). The obvious GMI effect obtained in the composite wires with conductive core frequency may provide a candidate for applications in magnetic sensors, especially at low frequencies.

Giant magneto-impedance effects in nanocrystalline soft magnetic alloy ribbons

SINCE the discovery of the giant magneto-impedance (GMI) effects in amorphous wire (or rib-bon) of CoFeSiB and nanocrystalline wire (or film) of FeCuNbSiB, it has attracted greatattention due to its promising potential applications in industry. Amorphous (and nanocrys-talline) soft magnetic alloys have very large magnetic permeability, when an ac driving currentand an external magnetic field (EMF) are applied, the EMF will damp the magnetic fluxchange caused by the ac driving current, thus the magnetic permeability will decrease; as a re-

Design and Fabrication of Magnetic Sensor Based on Giant Magneto-Impedance Effect

A large giant magneto-impedance effect was observed in CoFeSiB amorphous ribbon which was treated with the longitudinal field annealing in an atmosphere of Ar for one hour at 10-3 T and 400 ℃. The maximum magneto-impedance ratio is 475% and magnetic sensitivity of about 120%/Oe (1 Oe=80 A/m) at 20MHz, which is helpful to improve the sensitivity of magnetic sensor. The performances of the sensor were carefully studied in open-loop and closed-loop with negative feedback. The full measurement range of the magnetic field detection is 1.7-4 Oe presently, and the sensitivity achieves 176 mV/Oe. The sensor with negative feedback shows excellent linearity and good stability. The designed magnetic sensor can be applied in geomagnetic field measurement.

Giant magneto-impedance effect of two paralleled amorphous microwires

Giant magneto-impedance （GMI） is effectively enhanced by the mutual magnetic interaction between two amorphous microwires. A comparative study on GMI properties of a single wire and two wires arranged in par- allel mode was reported in this work. Two-peak （TP） of impedance characteristic is presented when the dc external field changed from 0 to 320 A,m-＇ in two-wire system, which is attributed to successive magnetization process in two wires induced by their magnetic interaction. And the evolution of single peak to TP phenomenon, when the distance between two wires is upto 8 ram, evidences a distance dependence of transformation from successive magnetization to simultaneous via a corresponding dis- tance dependence of magnetostatic interactions. It is pro- posed that the recombination of magnetic interaction and the shielding effect results in a distance dependency of GMI response. When the distance is 8 ram, the magneti- zation process is close to synchronous between two wires, which give rises to higher circular permeability and better GMI response. The impedance ratio AZ/Z increases from 74.5 % of single wire to 172.4 % at 10 MHz. However, when the distance is upto 12 mm, the magnetic interaction is weak and magnetization process is completely independent, and GMI response decreases, relatively. This indicates that the GMI response could be effectively improved in a two-wire connection with an optical distance, which is promising and useful for the application of high-performance GMI sensors.

GIANT MAGNETO-IMPEDANCE OF PATTERNED FeSiB/Cu/FeSiB TRI-LAYER FILMS

Sensitive magnetic field sensor with good performances can be fabricated utilizing the giant magneto-impedance (GMI) effect of soft magnetic multi-layer thin films. The transverse and longitudinal GMI effect in patterned FeSiB/Cu/FeSiB tri-layer films with the change of external magnetic field and frequency were studied at the same time. The change of the impedance of the films with the external magnetic fieldand frequency was shown. Comparing the longitudinal and transverse effect, the transverse effect has a larger linear range from zero magnetic field to a quite large magnetic field at all frequencies, and the change still were not saturated until the external magnetic field reached 1.2×104A/m, which illustrated that the films can be utilized to detect larger magnetic fields than now presented GMI sensors.

Giant magneto-impedance and permeability in Fe_(89)Zr_6Hf_1B_4 ribbons

The giant magneto-impedance (GMI) effect associated with the variation of transverse permeability for the ribbons Fe89Zr6Hf1B4 with different annealing temperatures T-A = 793, 823, 893, 923, 993, and 1033 K was investigated. There is an optimum annealing temperature TA = 993 K for obtaining the largest GMI effect for the ribbons Fe89Zr6Hf1B4. The magneto-impedance GMI (Z) = (Z(H) - Z(0))/Z(0) for the ribbon with T-A = 993 K can reach -55.09% at a frequency f = 900 kHz under H = 7162 A/m. The relative changes of the real part of transverse permeability Delta mu'/mu'(0) = (mu'(H)- mu'(0))/mu'(0) under H = 7162 A center dot m(-1) at f = 1 MHz are -78.83%, -89.98% and -94.77 % for Fe89Zr6Hf1B4 ribbons with T-A = 823, 893, and 993 K, respectively. The strong GMI effect is accompanied by the large change of transverse permeability. A large magnetoreaetance GMI(X) = (X (H) - X (0))/X (0) of -81.09% can be obtained at f = 100 kHz under H = 7162 A/m for the ribbon with T-A = 993 K. Meanwhile, this present result gave an experimental support to the previous concept / assumption that the positive peak in the field dependence of magneto-impedance is connected to the peak of transverse permeability with varying fields.

Giant Volume Magnetostriction Caused by Itinerant Electron Metamagnetic Transition and Pronounced Invar Effects in La(Fe_xSi_(1-x))_(13) Compounds

A first-order itinerant electron metamagnetic (IEM) transition above the Curie temperature Tc for ferromagnetic La(Fe_xSi_1-x)13 compounds has been confirmed by applying magnetic field. The volume change just above T_C for x=0.88 is huge of about 1.5%, which is caused by a large magnetic moment induced by the IEM transition. These compounds have a possibility for practical applications as giant magnetostrictive materials. Pronounced Invar effects bring about a negative thermal expansion below TC, closely correlated with the negative mode-mode coupling among spin fluctuations.

Giant magnetoimpedance effect in Fe-Zr-Nb-Cu-B nanocrystalline ribbons

The giant magnetoimpedance effect of the nanocrystalline ribbonFe_(84)Zr_(2.08)Nb_(1.92)Cu_1B_(11) (atom fraction in %) was investigated. There is an optimumannealing temperature (T_A≈ 998 K) for obtaining the largest GMI (giant magneto-impedance) effectin the ribbon Fe_(84)Zr_(2.08)Nb_(1.92)Cu_1B_(11). The ribbon with longer ribbon length has strongerGMI effect, which may be connected with the demagnetization effect of samples. The frequencyf_(max), where the maximum magnetoimpedance GMI(Z)_(max) = [(Z(H) - Z(0))/Z(0)]_(max) occurs, isnear the intersecting frequency f_i of the curves of GMI(R), GMI(X), and GMI(Z) versus frequency.The magnetoreactance GMI(X) decreases monotonically with increasing frequency, which may be due tothe decrease of permeability. In contrast, with the AC (alternating current) frequency increasing,the inagnetore-sistance GMI(R) increases at first, undergoes a peak, and under then drops. Theincrease of the magnetoresistance may result from the enhancement of the skin effect with frequency.The maximum magnetoimpedance value GMI(Z)_(max) under H = 7.2 kA/m is about -56.18% at f= 0.3 MHzfor the nanocrystalline ribbon Fe_(84)Zr_(2.08)Nb_(1.92)Cu_1B_(11) with the annealing temperatureT_A= 998 K and the ribbon length L = 6 cm.

Frequency dependence of magnetization and giant magneto impedance effect of amorphous wires

The frequency dependence of magnetization process and giant magneto impedance （GMI） effect of Co-rich melt-extracted amorphous wires was studied by Kerr effect and impedance analyzer, respectively. It is demonstrated that the transverse Kerr intensity and the corresponding GMI response increase with increasing frequency, which contributes to the upgraded skin effect. However, the skin depth has a slothful trend with frequency when it is up to the megahertz range, which gives rise to the transformation of magnetization. The process is much more sensitive to the direct current magnetic field and the sensitive change of the circular permeability, and GMI response is observed as its consequence. This proves that the evolution of circumferential magnetization and the corresponding permeability with the direct current magnetic field is the essence of GMI response, and a much more sensitive magnetization promises a better GMI response.

Giant Magnetoimpedance Effect of As-Spun Nanocrystalline Ribbon of FeZrBCu Alloy

The melt-spun nanocrystalline ribbons of Fe86.5Zr7B4Cu2.5 alloy were prepared by single wheel technique with wheel surface velocity of 37 m/s.It is found that there appears a lot ofα-Fe nanoparticles with sizes of 5-10 nm in as-spun nanocystalline ribbons which exhibit giant magnetoimpedance(GMI)effect.The GMI ratio up to 33.69% at frequency f=1MHz under a DC field of 5 172A/m can be obtained.

STUDY ON LIQUID-LIQUID EXTRACTION OF RESVERATROL FROM GIANT KNOTWEED AND ITS PROTECTIVE EFFECT ON MYOCARDIUM INJURY

Objective An efficient extraction and separation method of resveratrol from a Chinese herb giant knotweed was developed and the protective effect of resveratrol on myocardium injury was investigated.Methods An orthogonal experiment was utilized to optimize the extraction conditions and the pure white crystal obtained utilizing the proposed method was used for the investigation of myocardium ischemic injury.Results Resveratrol was found to have many beneficial activities including the protective effect on the heart and the scavenging of free radical.Conclusion The protective effect of resveratrol on myocardium injury is related to the quenching of lipid peroxidation.

Giant magnetoimpedance effect in as quenched Fe_(89-x)Zr_7B_4Cu_x(x=1.0-2.5) ribbons

The giant magnetoimpedance(GMI)effect in as-quenchedFe_89-xZr_7B_4Cu_x(x=1.0-2.5)ribbons is reported. The as-quenchedFe_89-xZr_7B_4Cu_x(x=1.0-2.5)ribbons were prepared by the vacuummelt-spun processes with the quenching speed of 37 m/s. The magne-Toimpedance measurement were performance at room temperature, wherethe current flow through the length of the ribbons in the directionParallel to the dc fields. results show that values Z(impedance),R(resistance)for both H = 0 A/m and H = 5 127 A/m Increases withincreasing ac frequency. This can be explained by the skin effectmechanism.

Giant Magnetoresistance Effect of [bcc-Fe(M)/Cu](M=Co,Ni) Multilayers

GMR effect of multilayers of bcc-Fe(M)(M=Co, Ni) alloy and Cu layers has been investigated. The maximum MR ratio is found at 1.1 nm Fe(Co) and 1.3～1.4 nm Cu layer thickness in [Fe(Co)/CuJ, and at 1.6 nm Fe(Ni) and 1.4 nm Cu layer thickness in [Fe(Ni)/Cu]. Under the optimum annealing condition, the MR ratio increases up to 50% and 38% for Fe(Co) and Fe(Ni) systems, respectively. The origin of the increase of GMR is discussed, taking the progress of preferred orientation of Fe(Co)[100] or Fe(Ni)[100] by anneahng into account.

Tuning Martensitic Phase Transition by Non-Magnetic Atom Vacancy in MnCoGe Alloys and Related Giant Magnetocaloric Effect

The effects of non-magnetic atom vacancy on structural, martensitic phase transitions and the corresponding magnetocMoric effect in MnCoGel-x alloys are investigated using x-ray diffraction and magnetic measurements. The introduction of non-magnetic atom vacancy leads to the decrease of the martensitic transition temperature and realizes a temperature window where magnetic and martensitic phase transitions can be tuned together. Moreover, the giant magnetocaloric effect accompanied with the coupled magnetic-structural transition is ob- tained. It is observed that the peak values of magnetic entropy change of MnCoGeo.97 are about -13.9, -35.1 and -47.4J.kg-1K-1 for △H = 2, 5, 7T, respectively.

ANTI-HUMAN LUNG GIANT CELL CANCER (PG) EFFECT OF HUMAN LAK CELLS IN VITRO AND IN NUDE MICE

Human LAK cells were prepared by culturing normal human peripheral blood mononuclear cells (PBMC) with or without rIL-2 and assayed for T cell surface markers as well as anti-tumor activity against PC in vitro and in nude mice. Although the percentages of T3, T4, and T8 positive cells in rIL-2-activated cells did not differ significantly from those of control cells in vitro, the former showed stronger cytotoxicity than control cells to PG tumor cells in vitro. In vivo, LAK cells completely inhibited the growth of PG tumor in nude mice, whereas PBMC control cells were to be of no effect. The anti-tumor effect of human LAK cells in nude mice may offer a useful model to study the role of human LAK cells against human tumor in vivo.

Applications of Quantum Physics on Resistivity, Dielectricity, Giant Magneto Resistance, Hall Effect and Conductance

Quantum theory with conjecture of fractional charge quantization, eigenfunctions for fractional charge quantization, fractional Fourier transform, Hermite function for fractional charge quantization, and eigenfunction for a twisted and twigged electron quanta is developed and applied to resistivity, dielectricity, giant magneto resistance, Hall effect and conductance. Our theoretical relationship for quantum measurements is in good conformity and in agreement with most of the experimental results. These relationships will pave a new approach to quantum physics for deciphering measurements on single quantum particles without destroying them. Our results are in agreement with 2012 Physics Nobel Prize winning Scientists, Serge Haroche and David J. Wineland.

Non-Ferrous Metal Giant Develops Effective Business Model

CNMC combines social responsibility with corporate vision as it expands in Africa TODAY non-ferrous metals(metals other than iron and alloys that do not contain an appreciable amount of iron) are an indispensable part of every aspect of our lives. From daily necessities like telephones and electric cookers,to sophisticated equipment like satellites and radar,non-ferrous

Improvement of giant magneto impedance of Co-rich melt extraction wires by stress-current annealing

In order to improve the giant magneto impedance （GMI） of Co-rich wires for high sensitive sensor applications, Co6sFe4.sSilsBlz5 wires were prepared by melt an extraction technique and subjected to Joule stress-current anneal treatments with different tensile slresses applied. And then their GMI response was investigated at a frequency range from 0.1 to 13 MHz. It was found through the comparison of results that the GMI effect of these wires had been improved through stress-current anneal treatments, because the tensile stress applied on these Co-rich wires introduced magnetoelastic energy and increased anisotropy, which improved the circular permeability and GMI effect. Their impedance ratio AZ/Z increased from 244% to 480.9% at 7 MHz and the field sensitivity increased to 0.83%/（A/m） at 5 MHz, when a tensile stress of 244 MPa was applied at an anneal current of 100 mA for 10 min. It was therefore concluded that these annealed wires were suitable for high sensitive sensor applications.

Spin-valley-dependent transport and giant tunneling magnetoresistance in silicene with periodic electromagnetic modulations

The transport property of electrons tunneling through arrays of magnetic and electric barriers is studied in silicene. In the tunneling transmission spectrum, the spin-valley-dependent filtered states can be achieved in an incident energy range which can be controlled by the electric gate voltage. For the parallel magnetization configuration, the transmission is asymmetric with respect to the incident angle θ, and electrons with a very large negative incident angle can always transmit in propagating modes for one of the spin-valley filtered states under a certain electromagnetic condition. But for the antiparallel configuration, the transmission is symmetric about θ and there is no such transmission channel. The difference of the transmission between the two configurations leads to a giant tunneling magnetoresistance （TMR） effect. The TMR can reach to 100% in a certain Fermi energy interval around the electrostatic potential. This energy interval can be adjusted significantly by the magnetic field and/or electric gate voltage. The results obtained may be useful for future valleytronic and spintronic applications, as well as magnetoresistance device based on silicene.