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The effects of different writing and reading temperatures on the switching voltage waveform, permeability, and flux state of standard nickel-copper-manganese and copper-manganese ferrite memory cores have been investigated over a temperature range of 0 to 70°C. These temperatures are well below the Curie temperatures of the materials being tested. It has been found that writing at a higher temperature than the read temperature leads to increased low temperature voltage switching thresholds, higher low frequency (<40 MHz) permeabilities, lower high frequency (>40 MHz) permeabilities, and flux states almost equal to the equilibrium value for the lower temperature. Read current pulse rise time and duration have been found to have no effect on the increase in threshold with temperature. Externally produced stresses have been used to simulate the effects of temperature changes on the core. 相似文献
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A method to overcome the residual drift problem inherent to M-H quasi-static hysteresis loop measurements is described. The solution is based on the magnetic hysteresis symmetry properties and was implemented in a computer-controlled inductive measurement system with frequency range 3-100 MHz for straight and circular samples particularly of soft amorphous and nanocrystalline alloys. Results obtained for several samples are presented showing the ability of the method to remove the residual drift. 相似文献
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When magnetic cores with a square hysteresis loop are used for a time delay Crcuit or a pulse counter circuit, and if these circuits are designed by the use of the static hysteresis loop, the ac magnetization curve, or the control magnetization curve (CMC) which is the basic characteristic of a magnetic amplifier, there is apt to be a marked discrepancy between their design values and measured values. Since, in the flux control of magnetic cores used for a time delay circuit or a pulse counter circuit, the flux, contrary to the case with a magnetic amplifier, arrives at the negative saturation from the positive saturation by many intermittent signal voltages, a new characteristic quite different from CMC and other characteristics must be adopted as the standard of the design in this case. It was for this reason that instantaneous relation between the rate of flux change and the exciting current was examined in the case in which real flux resetting behaviors of a time delay circuit or a pulse counter circuit were taken into consideration, by using grain-oriented 50 per cent permalloy as the sample, with a view to obtaining core characteristics serviceable enough for exact design methods of a time delay circuit or a pulse counter circuit. Various useful results have been obtained as to: 1) how the correlation between rate of flux changedPhi/dt and instantaneous values of exciting current ic changes in proportion to the flux values, 2) how the amount of reset fluxDeltaPhi_{r} will change according to the flux valuePhi and the rate of flux changedPhi/dt , and 3) how the above-mentioned relations are connected to the tape thickness of the magnetic core. This paper reports the results of this investigation. 相似文献
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Luo F Eimüller T Amaladass E Lee MS Heyderman LJ Solak HH Tyliszczak T 《Journal of nanoscience and nanotechnology》2012,12(3):2484-2488
Using scanning transmission X-ray microscopy combined with X-ray magnetic circular dichroism, element-specific hysteresis loops with a 25 nm X-ray probe are obtained on 35 nm Fe/Gd multilayer nanoislands fabricated by extreme ultra-violet interference lithography. Local hysteresis loops measured for the individual islands and the antidot film between the islands display similar behavior resulting from the lateral confinement. Line scan measurements confirm ferrimagnetic coupling between Fe and Gd in the patterned region. The ability to measure magnetization reversal with X-rays at high spatial resolution will provide an important tool for future characterization of sub-50 nm nanostructures. 相似文献
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Li H Subramanyam G Dey S 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2008,55(2):286-292
Hysteresis loops of Pb(Zr, Ti)O3 (PZT) thin films obtained by using a Sawyer-Tower (ST) circuit are affected by many factors. This paper investigated the influence of space charge on the hysteresis loop of thin-film ferroelectrics, based on the model that polarization consists of two parts: linear and switching polarization. It is found that the space charge affects both the shape and offset of the ideal hysteresis loop. Further investigation shows that the practical hysteresis loop has a close relationship with the equivalent ST circuit parameters: the leakage resistance of the FE film, the equivalent input impedance of the measurement equipment, the signal source, and other similar parameters. The normally assumed symmetric hysteresis loop without any offset is obtained with an ST circuit when the output becomes stable. The hysteresis loop obtained at the initial stage of applied signal depends on the initial status of the FE film, and remnant polarization causes an initial offset that gradually disappears. 相似文献
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Reversible and irreversible changes in magnetization due to stress on a minor hysteresis loop were studied at various magnetic field strengths. It was found that the irreversible changes were not always directed toward the principal anhysteretic, contrary to Jiles and Atherton's hypothesis (1986). Also, two different demagnetization methods were used within the minor loop to test the existence of postulated offset anhysteretic curves. The results of asymmetric demagnetizations seemed to support this suggestion 相似文献
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A procedure for the determination of the parameters of actual diagrams of cyclic deformation is developed on the basis of
experimental and theoretical investigations of cyclic stress-strain diagrams for steels. This diagram characterizes the dependence
of strains on stresses in a loading cycle in the region of the transition from low-cycle fatigue to multicycle and proper
multicycle fatigues. The correspondence between the amplitudes of plastic and residual deformations is established and the
formula for the determination of the form factor of a hysteresis loop is proposed. Numerical data are compared with experimental
results for 45 and 15313 steels and with data obtained by other authors.
Translated from Problemy Prochnosti, No. 3, pp. 30–38, May–June, 1997. 相似文献
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We investigated the power-frequency bistability of a grating external cavity laser diode (ECLD), which operates in the strong feedback regime, by studying the threshold carrier density and related refractive index. The frequency width of the hysteresis loop has been expressed in an explicit analytical form in terms of the linewidth enhancement factor, and the reflectivities of the external grating reflector as well as the diode facet that faces it. 相似文献