Magnetic-Domain Structure Analysis of Nd-Fe-B Sintered Magnets Using XMCD-PEEM Technique

A combination of X-Ray Magnetic Circular Dichroism and PhotoEmission Electron Microscopy (XMCD-PEEM) was applied to the magnetic domain analysis of Nd-Fe-B sintered magnets. The XMCD-PEEM high-resolution images revealed both the magnetic domain structures and the microstructural morphologies. In the thermally demagnetized state, each grain in a polycrystalline sample exhibits a multidomain structure, which is magnetically coupled across grain boundaries. After the DC field-demagnetization, it changed to a single domain structure. The magnetization vector in each surface grain reversed to the negative direction during the field-demagnetization procedure because of the small coercivity in the surface region. In the present study, we observed this surface domain reversal for the first time by means of XMCD-PEEM imaging method, which is important in order to understand the surface phenomena of Nd-Fe-B magnets

Исследование реологических свойств биополимерных буровых растворов с использованием понизителей фильтрации на основе КМК и ПАЦ

Исследование биополимерных растворов первичного вскрытия на основе карбоксиметильных эфиров крахмала и целлюлозы.Research of biopolymer solutions of primary opening on the basis of carboxymethyl esters of starch and cellulose

Lattice Softening in Fe3Pt Exhibiting Three Types of Martensitic Transformations

We have investigated the relation between the softening of elastic constants and martensitic transformation in Fe3Pt, which exhibits various kinds of martensitic transformation depending on its long-range order parameter S. The martensite phases of the examined alloys are BCT (S = 0.57), FCT1 (S = 0.75, c/a < 1) and FCT2 (S = 0.88, c/a > 1). The elastic constants C′ and C44 of these alloys decrease almost linearly with decreasing temperature. Although the temperature coefficient of C′ decreases as S increases, C′ at the transformation temperature is the smallest in the alloy with S = 0.75, which transforms to FCT1. This result implies that softening is most strongly related to the formation of the FCT1 martensite with tetragonality c/a < 1 among the three martensites