Toshinao Yamaguchi

Localized magnetic properties in grain‐oriented electrical steel measured by needle probe method

The accuracy of a needle probe method in measuring localized magnetic properties of grain-oriented electrical steel sheets was investigated and its application studied. The measuring error for the localized flux density was determined to be less than 1.7% for a load on the needle tip lighter than 300 g when the yoke structure was symmetrical with respect to the sheet plane. The average of localized iron losses measured with the combination of a needle probe and a Hall probe was in linear relation to the overall losses in the sheet. This method revealed that the localized magnetic properties vary markedly from location to location inside the sheet, and that localized iron loss depends on the localized flux density, domain wall spacing, and yaw angle of grain orientation.

Local magnetic properties in grain-oriented electrical steel measured by the modified needle probe method

Distribution of local magnetic properties in grain-oriented electrical steel was investigated using the needle probe method. The spatial nonuniformity of flux density was found to be affected by magentic poles on grain boundaries which mainly depend on the α angles between neighbouring grains and on the direction of grain boundaries.

Effects of crystallographic misorientation on power loss in

The effects of the inclination angle β of the [001] axis out of the sheet plane on the thickness dependence of the power losses in

Structures and magnetic properties of iron–nitrogen alloy powders prepared by mechanical alloying process

Abstract An investigation of forming iron–nitrogen solid solution was made by applying a mechanical alloying process to the mixture of Fe and Fe 4 N powders. Following the collapse of the FCC structure of Fe 4 N at an early stage of milling process, a single phased structure which could be regarded as BCC-like Fe–N solid solution was formed. A certain amount of increase in magnetization due to formation of this Fe–N alloy was observed.

Automatic Measurement of Preisach Distributions in Soft Magnetic Materials

The mathematical formalization of Preisach distribution was studied. A peak was observed with its center on the line hi = hk (45°) in the Preisach distributions of a non-oriented silicon steel plate S-10 and a grain-oriented silicon steel plate G-7. In the neighborhood of the main peak a valley with negative distribution value can be seen and adjacent to it is a ridge of positive distribution values. This result is due to the fact that magnetization reversal is more difficult in minor loops with larger returning magnetic fields.

Torque analysis of Co-Cr films prepared under different Ar pressures

This paper describes the results of torque analysis on the Co-Cr 17-18 at.% sputtered films prepared with the controlled Ar gas pressure (P/sub Ar/) at 4-70 mTorr. At lower P/sub Ar/ (P/sub Ar/ 20 mTorr which indicates the occurrence of incoherent magnetization rotation.

Simulation of Hysteresis Characteristics of Core Materials Using the Everett Function

The recent development of methods for numerical analysis of the magnetic flux in electrical equipment has given rise to a need for an accurate characterization of magnetic hysteretic processes in core materials. In this investigation, the idea of the Everett function, which is an integral form of the Preisach density function, was applied to simulations of the hysteresis curves of core materials in use. The Everett function of various core materials was measured using a microcomputer-controlled hysteresis tracer, and a mathematical formulation of the function was obtained. The formula can predict the hysteresis curves of various materials with good accuracy.

Automatic Measurement of Magnetic Domain and Bloch Wall Distributions on 3 Percent Si-Fe Sheet by Means of Hall Sensor

The authors describe apparatus for the highly accurate measurement of stray magnetic fields in a modification of Pfützners method, and discuss the relation between the stray field distribution and basic 180° domains in (100), [001] 3 percent Si-Fe single-crystal sheets. A GaAs Hall element connected to a precision positioning device was used to detect normal field components on the sheet surface. The positions of Bloch walls, as determined by mapping from field measurements, agreed well with the positions from domain pattern photographs. The field was found to be greatest at the centers of domains, and the effect of scratching in reducing the stray field was also studied.

Everett Function of Soft Magnetic Materials

Often, in detailed analyses of the characteristics of magnetic cores used in electrical equipment, the hysteresis of the core material must be taken into consideration. To do so, a numerical expression for the hysteresis characteristics of the material becomes necessary. One method which in principle can be used to express any arbitrary magnetization behavior is the Preisach model. The authors previously reported the results of measurements of Preisach distributions of various core materials; fairly complex distributions were obtained, making numerical formulation difficult. However, on using the Everett function to simulate the hysteresis behavior of different soft magnetic materials, quite good results were obtained, and are described.

Hysteresis Loss in Thinned Single Crystals of 3% Si-Fe

The relation between the inclination angle of the [001] axis ß and hysteresis loss in Si-Fe single crystal sheets was studied. No appreciable increase in the range 0° to 2° was found, but from 2° to 3° rapid increase was observed. This seems to be due to the facts that when ß is in the low angle range below 2°, surface closure domains exist separately and independently, and above 2° the closure domains couple together and form an aggregate structure.