Quasi-static Hysteresis Loops Research Articles

Slow hysterisis loops in irradiated TGS crystals

Abstract An almost non-disturbing method to plot quasistatic ferroelectric hysteresis loops was used to study TGS single crystals subjected to accumulative X-radiation. The hysteresis loop disappearance depends exclusively on the magnitude of the applied electric field. If the field increases the hysteresis loop still persists. The mechanism of polarization reversal is modified only in the direction of the polarization opposite to that during the irradiation time. Therefore, it is not correct to talk about an irradiation induced bias field as one usually does. The whole polarization is also measured through the polarization-temperature patterns. When the hysteresis loop disappears with the irradiation, P is still observed in the P-T diagram and its value is the same as for an un-irradiated crystal; also the transition temperature remains unchanged.

Automatic recorder of static hysteresis loops in magnetically hard materials

1. The experimental investigation of precision obtained in the equipment for recording hysteresis loops of magnetically hard materials has shown that it is inadvisable to calibrate it by means of a ballistic installation, since the errors of the two methods are of the same order. A theoretical analysis indicates that the total error of the newly developed equipment amounts to 1.5%. 2. The labor consumed in recording hysteresis loops with the new equipment is considerably smaller than that of the ballistic installation. The recording and processing time does not exceed 5 min. At present the new installation is semiautomatic, since it requires manual trimming of the magnetizing current wave-form. Complete automation of the hysteresis-loop recording is considered possible on the basis of the produced model and experimental criteria. 3. The equipment is suitable for recording quasistatic hysteresis loops. The measuring unit drift and the integration constant are suitable for studying specific remagnetization cycles and their position with respect to the basic magnetization curve. 4. The sensitivity and precision of the measuring unit are adequate for studying the effect of temperature on the static characteristics of ferromagnetic materials. The utilization of inductive transducers does not limit the temperature range. 5. The wave-form of the magnetizing current makes it possible to reduce the nominal power of the current sources (dynamoelectric generator) and decrease the size of the electromagnets.

Magnetic Ceramics: V, Magnetic Properties of Square Loop Ferrites Within the System MgO‐MnO‐Fe2O3

Thirteen compositions within the center of the system MgO‐MnO‐Fe2O3 were investigated because of their rectangular hysteresis‐loop characteristic. Initial permeabilities were measured, and Bm, BT, Hc, and R8m were obtained from quasi‐static hysteresis loops. High MgO content was found to be detrimental to the magnetic properties and to impair the loop rectangularity. The highest hysteresis‐loop squareness ratio, R, 8m, was found in a composition with high Fe2O3 content, and the lowest coercive force, Hc, was found in a composition with high MnO content.