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The purpose of this work was to study the influence of different kinds of rolling on the magnetic properties of NOG steel, an electric steel widely used in electrical motors. These properties are highly correlated with the crystallographic texture of the material, which can be changed by rolling. Three kinds of rolling were examined: conventional rolling, cross-rolling and asymmetrical rolling. The crystallographic texture was determined by X-ray diffraction and the magnetic properties were calculated from a theoretical model that related the magnetic induction to crystallographic texture through the anisotropy energy. The results show that cross-rolling yields higher values of magnetic induction than the other processes.

This paper reports the evolution of microstructure and texture in Nickel-Cobalt electrodeposits fabricated by pulse electrodeposition (PED) technique and the correlation of these attributes with the magnetic properties. The structural and microstructural investigation using X-ray diffraction and transmission electron microscopic studies indicate the presence of nanocrystalline grains and nano-twins in the electrodeposits. Convoluted Multiple Whole profile fitting reveals an increase in dislocation density and twin density with increasing cobalt content in the as-deposited samples. Strengthening of fibre texture and weakening of fibre texture with increasing cobalt concentration has been observed with X-ray texture analysis. A corresponding significant increase in the saturation magnetization and coercivity observed with increasing cobalt content. A significant improvement in the soft magnetic character in the electrodeposits in terms of increase in saturation magnetization and decrease in coercivity has been observed with thermal annealing. (C) 2017 Elsevier B.V. All rights reserved.

The effect of magnetic annealing on crystallographic texture, microstructure, defects density and magnetic properties of a Fe-2.6% Si steel has been analyzed. After two stage cold rolling (75% and 60% cold rolled) with intermediate annealing process at (600 °C/1 h) the sample annealed at 600 °C for one hour during which different magnetic field of 0, 7 and 14 T were applied has been investigated. The effect of defects density after cold rolling process on the recrystallization texture and magnetic properties was characterized. Heat treatments under a high external field of 14 T show a drastic improvement of the magnetic properties such as significantly increased permeability. Neutron diffraction measurements were preferred for measurement of the bulk sample texture so that sufficient grain statistics were obtained. Because of its small wavelength (0.05–0.2 A) Synchrotron diffraction with high photon energy was used to evaluate the defects density by a modified Williamson–Hall plot.

Quantitative physical models for non-oriented electrical steels require precise knowledge of chemical and microstructural parameters for the material, with crystallographic texture being one of the most important. Describing the structure–property relationships in these materials is made difficult in that all of the parameters have an effect on magnetic properties. In the present study, a set of non-oriented electrical steel specimens are examined, where chemistry and grain size are kept similar from sample to sample, but texture is varied. A new texture parameter called Magnetic Texture Factor is introduced which is defined as the ratio of the volume fractions of 〈100〉 direction to 〈111〉 direction along magnetization vector. It was found that this Magnetic Texture Factor was a better parameter for identifying trends of magnetic properties with crystallographic texture than the often used Texture Factor , which is described as the ratio of the volume fractions of {100} planes to {111} planes.

CeCo5.4 ribbons have been prepared by melt spinning at wheel speeds v=5, 15, 25 and 35 m/s. The ribbons are essentially single 1:5 phase, and have significant crystallographic texture and magnetic anisotropy. The ribbon's longitudinal direction is easy direction, and normal to the ribbon plane direction is hard direction. For v=5 m/s [1 1 1]-axes of the grains near non-contact surface of the ribbon are normal to the ribbon plane. With increase of v, [1 1 0] and [2 0 0]-axes of the grains near non-contact surface rotate toward the normal direction and the c-axes parallel to the ribbon plane. The anisotropy increases up to v=25 m/s and then decreases. The grains near contact-wheel surface are randomly oriented for all v. The coercivity increases with increase of v due to decrease of the grain size. The values of coercivity are smaller in the easy direction and are larger in the hard direction, meaning that the coercivity mechanism is mainly characterized by domain wall pinning.

A combination of hydrogen decrepitation and planetary ball milling has been used to produce sintered Pr 16 Fe 76 B 8 magnets. The effects of key process parameters and texture have been studied. The alignment degree (〈cos Θ 〉) has been investigated by X-ray pole figure analysis using the (0 0 4) reflection. Magnets prepared from the alloy decrepitated for 3.6 ks and milled for 1.8 ks exhibited a low degree of crystal alignment (0.71±0.02) due to polycrystalline particles. Increasing the milling time to 4.5ks has led to an improvement in 〈cos Θ 〉 to 0.84±0.02. This has been ascribed to the smaller particle size with a narrower size distribution as well as a more favorable particle shape for orientation. Superior alignment degree (〈cos Θ 〉=0.88±0.02) has been achieved for the sintered magnet from the alloy decrepitated for 120 s and milled for 5.4 ks. This particular processing condition has led to a magnet with (BH) max =250±5 kJ m −3 , value found in magnets produced using roller ball milling, with the advantage of a reduced milling time (about 90%).

In this study, magnetic domains in Pr16Fe76B8 sintered magnets have been observed by Kerr effect and a histogram of the angular distribution of domain orientations has been used to determine the magnetic texture (〈 cos Φ〉) . The degree of easy-axis alignment of Pr2Fe14B matrix grains in these magnets has been also determined by X-ray pole figure analysis using the (0 0 4) reflection. The (0 0 4) pole figure measurements were carried out by the Schultz's reflection method. The (0 0 4) normalized intensity data has been fitted for a Gaussian distribution and the degree of crystal alignment, 〈 cos Θ〉 , has been calculated using the Stoner–Wohlfarth model. Comparison of these methods has been carried out. It has been shown that in magnets with medium and high degrees of crystallographic alignment, the pole figure values are higher than that obtained by the Kerr effect method. Conversely, in magnets with low degrees of alignment, 〈 cos Θ〉 is lower than 〈 cos Φ〉 .

The internal coercive field has been associated with the minimum force counteracting the motion of 180° Bloch walls, which depends on the relative orientation between the crystal axes and the magnetisation direction. The minimum force is related both to the texture-dependent components of the hysteresis loss and to the internal coercive field derived from the statistical loss model by Bertotti. Correlations have been also found with the fitting parameters of a previously presented magnetostriction model.

An alternative method for determining the degree of crystallographic alignment (〈cos Θ 〉) of the magnetic Pr 2 Fe 14 B phase (Φ) is proposed. The method is based on the relative X-ray diffracted intensities of the Φ planes of sintered magnets with and without texture. The degree of crystallographic alignment is also determined by X-ray pole figures using the (0 0 4) reflection and considered as a standard reference for comparison. The method is applied to Pr 16 Fe 76 B 8 magnets with 0.51⩽〈cos Θ 〉⩽0.97. The difference between the crystallographic alignments determined by these two methods is 3% within the experimental error. The advantages and limitations of using X-ray diffraction patterns to quantitatively evaluate the texture of sintered magnets are also discussed.

Texture of CoCrMn alloy thin films with varing Mn content was investigated by X-ray diffraction. HCP (Co 64 Cr 36 ) 100-x Mn x (5 < x < 12) thin films showed the spontaneous in-plane texture when grown on a heated glass substrate. Strong (1 0 1 0) texture of CoCrMn thin films appeared only with proper Mn addition while Co 64 Cr 36 thin film showed random orientation.

A quantitative way to correlate magnetic property to texture is by means of average magnetocrystalline energy E a . In the present work, E a was calculated from texture measurements determined by X-ray diffraction. It was observed the presence of texture gradient in the sample thickness direction. In order to determine the average texture, the measurements were performed on RD section and two computer programs were developed to analyze the X-ray texture data. The relation between J50 and E a is a first degree equation.

Although theoretical models have already been proposed, experimental data is still lacking to quantify the influence of grain size upon coercivity of electrical steels. Some authors consider a linear inverse proportionality, while others suggest a square root inverse proportionality. Results also differ with regard to the slope of the reciprocal of grain size–coercive field relation for a given material. This paper discusses two aspects of the problem: the maximum induction used for determining coercive force and the possible effect of lurking variables such as the grain size distribution breadth and crystallographic texture. Electrical steel sheets containing 0.7% Si, 0.3% Al and 24 ppm C were cold-rolled and annealed in order to produce different grain sizes (ranging from 20 to 150 μm). Coercive field was measured along the rolling direction and found to depend linearly on reciprocal of grain size with a slope of approximately 0.9 (A/m)mm at 1.0 T induction. A general relation for coercive field as a function of grain size and maximum induction was established, yielding an average absolute error below 4%. Through measurement of B50 and image analysis of micrographs, the effects of crystallographic texture and grain size distribution breadth were qualitatively discussed.

A significant advance in the understanding of grain boundary contribution to magnetization in nanocrystalline ferrite thin films is demonstrated in this paper. RF-sputtered, room-temperature-deposited lithium–zinc ferrite thin films (Li 0.5− x /2 Zn x Mn 0.1 Fe 2.35− x /2 O 4 , with x =0.0, 0.16, 0.32 and 0.48) have been thermally annealed ex-situ at 850 °C and the in-plane magnetic measurements have been performed using a vibrating sample magnetometer. The percentage deviation between bulk and film magnetization ( δ M ) is observed to decrease with increasing Zn concentration, till x =0.32, and then it increases. Macro-texture measurements using X-ray orientation distribution function and micro-texture measurements using orientation imaging microscopy show reverse trend in the extent of crystallographic texturing and in the computed fraction of low-angle grain boundaries. This study brings out a correlation between low-angle grain boundary concentration and δ M .

Fabricating anisotropic bulk rare-earth (RE)-free magnets with both crystallographic texture and refined grains is a difficult task. In this paper, an anisotropic bulk Mn-Al-(C) RE-free magnet with a (00l) crystallographic texture was fabricated using the confined deformation under high-stress and large-strain conditions during the phase transformation from hexagonal e-phase to tetragonal τ-phase. XRD patterns of the magnets revealed that the τ-phase with grain sizes of 150–200 nm is the predominant phase and that the magnets exhibit a (00l) texture perpendicular to the pressure direction. The deformed magnets have an obvious magnetic anisotropy and enhanced remanence perpendicular to the pressure direction due to the texture formation. The effects of deformation temperature (Td) and time (t) on microstructures and magnetic properties of these magnets were investigated, and optimal magnetic properties, with a coercivity of 239 kA/m (3 kOe) and energy product of 14.5 kJ/m3 (1.82 MGOe), were obtained at Td = 550 °C and t = 60 s. Our work is of importance for future development of high-performance anisotropic bulk RE-free magnets.

Non-oriented electrical steel (NOES) is one of the most common material used in electrical motors. Core loss and permeability are the most important properties that the motor manufacturers look for. Both these properties are structure sensitive and depend on several metallurgical factors; such as chemistry, grain size, crystallographic texture, cleanliness and stress states in non-oriented electrical steels. It has been observed in this course of the study that the grain size and Si content of NOES are the primary controlling factors to core loss, especially at higher frequencies. On the contrary, crystallographic texture plays an important role at lower frequencies. At higher frequency, core loss increases with increasing grain size and decreasing Si content of the steels. Small difference in grain size (~50 μm) at lower frequency range has little influence on the magnetic properties but has significant adverse effect as frequency reaches high enough.

Commercial supply, from several steel manufacturers, of low-silicon non-grain-oriented electrical steel was monitored over a span of several years. A total of 51 samples were selected—selected from many hundreds on the basis of large differences in magnetic properties, but absence of significant variations in chemistry (other than differences in silicon percentage). The selected samples were analyzed for crystallographic texture and for grain size. The data were carefully analyzed to bring out the effects of metallurgical variables, namely silicon %, grain size and crystallographic texture, on the magnetic properties using explicit functional relationships as well as artificial neural network (ANN). Among the explicit relationships, power law relationship appears to offer a best fit between magnetic properties and the metallurgical factors. ANN approach to the relationship, however, brought out predicted values with least error.

Anisotropic YCo5 ribbons have been obtained by melt spinning arc-cast ingots of the alloy. The surface velocity of the Cu roll was varied between 25 and 48.5 m/s. Magnetic anisotropy was observed, reflecting crystallographic texture associated with the ribbon solidification process, with the c-axis preferentially aligned parallel to the ribbon plane. The crystallographic texture is attributed to directional solidification induced by the thermal gradient. Ribbons obtained with a roll velocity of 48.5 m/s exhibited an intrinsic coercivity of 7.8 kOe, a high M r / M s ratio of 0.75 and a ( BH ) max = 7.11 MGOe at room temperature. The high coercivity is attributed to the high anisotropy field of the YCo5 phase and to its nanoscale grain size.

The soft magnetic properties of Fe-Co-Al-O films deposited by sputtering (Fe 70 Co 30 ) 99 (Al 2 O 3 ) 1 on a variety of underlayers have been investigated. A remarkable reduction in coercivity, H c , was found in Fe-Co-Al-O films sputtered on underlayer materials, such as Au, Ag or Cu, that have a surface-free energy in the region of 1-2 J/m 2 . All underlayers induced a BCC-(110) preferred grain orientation in the Fe-Co-Al-O films, although this effect was weak for Au, Ag and Cu. When the surface free energy of the underlayer material is higher than 2 J/m 2 , as in the case of Hf, Fe-Co-Al-O films can be grown with a well-defined BCC-(110) crystallographic texture. The primary effect of varying the underlayer in Fe-Co-Al-O bilayer structures is to change the crystallographic texture of the Fe-Co-Al-O films due to the difference in surface-free energy. Transmission electron microscopy performed on cross-sections revealed the presence of clear columnar grains for all underlayers, with an average size of approximately 50 nm for Hf, dropping to 5-7 nm for Au, Ag and Cu. This allows us to explain qualitatively the reduction in He using Hoffman's ripple theory.

We have succeeded in preparing magnetically anisotropic SmCo5 ribbons with high permanent performance by single-roller melt spinning at low wheel velocity. The anisotropy is associated with a crystallographic texture formed during melt-spinning process, with the c-axis parallel to the longitudinal direction of the ribbons. The formation of the crystallographic texture is attributed to a directional solidification process resulting from a thermal gradient. A remanence of 9.1 kG, remanence ratio of 0.9, intrinsic coercivity of 16.2 kOe and energy product of 18.2 MGOe at room temperature are obtained in the melt-spun and subsequently annealed SmCo5 ribbons prepared at 5 m/s. (C) 2000 Elsevier Science B.V. All rights reserved.

In this paper, the relation of the microstructural properties of electrical steels and the material parameters in the dynamic Preisach model is established. Particular experimental work was performed in order to separate the influence of grain size from the crystallographic texture. First, the parameters defined in the dynamic Preisach model has been fitted using the hysteresis loss characteristics. Next, we identified and separated the effect of average grain size from the crystallographic texture on each material parameter defined in the Lorentzian–Preisach distribution function. Here, the same texture dependence was identified for all kinds of magnetisation processes, i.e. for the irreversible and reversible parts of the quasi-static magnetisation and for the AC excess loss behaviour. Finally, the Preisach distribution function is rewritten explicitly including the grain size and crystallographic texture dependence.

In the present work a model for the correlation between magnetocrystalline anisotropy energy and Barkhausen noise is proposed. The link between the magnetocrystalline anisotropy energy and the magnetic Barkhausen noise is due to the influence of the crystallographic texture on the domain nucleation process which produces the Barkhausen signal in the branch from saturation to remanence. The statistical distributions of magnetic free poles and local fields of nucleation and subsequent growth of reversed domains were obtained for a large number of grain boundaries and used to estimate the number and size of Barkhausen events at each angular position from 0 to 360° in ten degree-steps. The good agreement observed between the modeled magnetocrystalline energy and the prediction of this energy made from X-ray texture and Barkhausen noise measurements corroborates the validity of the proposed model.

Magnetic Barkhausen noise (MBN) signals were measured on a non-oriented electrical steel through all the thermomechanical processing stages, i.e. hot rolling, hot band annealing, cold rolling and final annealing. The temperature of the final annealing was varied from 600 °C to 750 °C so that the steel consisted of partially or completely recrystallized microstructures and different levels of residual stresses. The angular MBNrms (root mean square) values were compared to the texture factors in the same directions, the latter being calculated from the crystallographic texture measured by electron backscatter diffraction (EBSD). It was found that, in the cold-rolled, hot-rolled and completely recrystallized steels, the angular MBNrms followed a cosine function with respect to the angle of magnetization, while in partially recrystallized state such a relation does not exist. After cold rolling, the maximum MBNrms was observed in the rolling direction (RD) and the minimum MBNrms was in the transverse direction (TD), which was inconsistent with the magnetocrystalline anisotropy as indicated by the texture factor. After hot rolling, the maximum and minimum MBNrms values were observed in the TD and RD, respectively, exactly opposite to the cold-rolled state. If the steel was completely recrystallized, the maximum MBNrms was normally observed at a direction that was 15–30° from the minimum texture factor. If the steel was partially recrystallized, both the magnetocrystalline anisotropy of the material and the residual stress contributed to the angular MBNrms, which resulted in the deviation of the relationship from a cosine function. The relative strength of the two factors determined which factor would dominate the overall magnetic anisotropy.

In this paper, the effects of annealing on grain-boundary character distribution and texture evolution were investigated in hot-rolled Fe-6.5 wt% Si steel. An annealing treatment performed at different temperatures affected the recrystallization behavior and changed the volume fraction of low-angle and coincidence site lattice (CSL) boundaries. High frequencies of coincidence boundaries Σ3, Σ9, Σ13, and Σ27 were observed in all annealed samples, while the annealing temperature can lead to a large difference in frequencies for Σ13. The effect of crystallographic texture on the directional dependence of the specific magnetic energy in the rolling plane of investigated sheets was calculated and discussed. These results demonstrate the possibility of optimizing grain-boundary character distribution (GBCD) and texture to improve the magnetic and mechanical properties of Fe-6.5 wt% Si steel by controlling annealing temperature.

The phase formation, crystal structure, crystallographic texture, microstructure and magnetic properties of Alnico-8 alloys with varying Co and Nb content have been investigated and presented. Alnico-8 alloys were fabricated by induction melting and casting techniques. Magnetic properties in the alloys were induced by optimized thermomagnetic treatment and subsequent aging. The 37.9Fe-32Co-14Ni-7.5Al-3.1Cu-5.5Ti alloy exhibits coercivity of 110 kA/m, remanence of 0.66 T and energy product of 31.2 kJ/m 3 . The addition of 35 wt% Co in conjunction with 1.5 wt% Nb to 37.9Fe-14Ni-7.5Al-3.1Cu-5.5Ti alloys led to increase the magnetic properties, especially coercivity. The enhancement of the coercivity is attributed to ideal shape anisotropy and optimum mass fraction of ferromagnetic Fe-Co rich particles, which are 25–30 nm in diameter and 300–350 nm in length. The 33.4Fe-35Co-14Ni-7.5Al-5.5Ti-3.1Cu-1.5 Nb alloy yields the optimum magnetic properties of coercivity of 141.4 kA/m, remanence of 0.83 T and energy product of 42.4 kJ/m 3 . The good magnetic properties in the studied alloys are attributed to the nanostructured microstructure comprising textured Fe-Co-Nb rich α 1 phase and Al-Ni-Cu rich α 2 phase.

The magnetic properties of the finally fabricated nonoriented FeSi steels critically depend on the microstructure and on the occurring crystallographic texture. The fabrication route comprises hot rolling, coiling and cooling, hot band annealing before cold rolling (optional), cold rolling and the final thermal treatment. As well known there is an interplay between the microstructure and texture during the various processing steps. For that reason, it is of interest to know more on the evolution of the microstructure at hot band annealing of hot band prepared in different ways. In this paper we will summarize our recent results on the evolution of microstructure during thermal annealing of hot band: thermal treatment following immediately the last pass of hot rolling or a hot band annealing as a separate processing step before cold rolling.

Rare-earth-lean Sm(Fe,Co,Ti)12 alloys with the ThMn12 crystal structure and less than one Ti atom per formula unit have the potential of exceptionally powerful permanent magnets, but all prior attempts to develop high coercivity in bulk alloys, especially coercivity combined with crystallographic texture, have fallen short of the expectations. This study was aimed at improvement of the currently best Sm(Fe,Co,Ti)12 magnets prepared through melt-spinning which are inherently isotropic. Modifications of the alloys with B and Zr, already demonstrated in earlier studies to be effective separately, have been implemented simultaneously. A systematic study of Sm1.1-x(Fe,Co)11.3-yTi0.7By alloys melt-spun at a tangential speed of 50 m/s and annealed at 600–950 °C allowed for monitoring the continuous evolution of the two consecutive crystal structures, those of the TbCu7 and ThMn12 types. Zirconium was found to facilitate the formation of the 1:12 structure at the expense of the 1:7, whereas boron has the opposite effect, at certain concentrations completely suppressing the 1:12. When the two alloying elements are introduced simultaneously, they inhibit growth of the 1:12 crystallites at annealing temperatures higher than 800 °C, thus allowing for the development of a higher coercivity. Because of instrumental limitations, bulk magnets were prepared through a two-step process – compaction of the melt-spun ribbons at 650 °C and additional treatment at a higher temperature – and they were characterized by a reduced, 90–93%, density. Nevertheless, an isotropic Sm0.9Zr0.2(Fe,Co)10.8Ti0.7B0.5 magnet exhibited fair values of the remanence (7.4 kG), maximum energy product (8.5 MGOe) and coercivity (5.4 kOe), as well as high Curie temperature of 525 °C and remarkably small temperature coefficient of the coercivity, −0.25%/°C.

Two non-oriented electrical steels containing 0.9 wt% and 2.8 wt% of silicon were processed using an unconventional cold rolling scheme, i.e. the cold rolling direction (CRD) was intentionally inclined at an angle to the hot rolling direction (HRD) so that the initial texture before cold rolling and the rotation paths of crystals during cold deformation were both altered as compared to conventional cold rolling along the original HRD. The cold-rolled steel strips were then annealed, skin-pass rolled and final annealed. The texture and microstructure of the materials were characterized by X-ray diffraction (XRD), electron backscatter diffraction (EBSD) and optical microscopy, and considerable differences in average grain size and texture were observed at different inclination angles. The magnetic properties of the steel strips were measured at 400 Hz and 1.0 T/1.5 T using a specially designed Epstein frame, and apparent differences were also noticed at various angles. The magnetic quality of texture was evaluated using different texture factors/parameters and compared to the measured magnetic properties. Although apparent improvement on the magnetic quality of texture can be noted by inclining the CRD to HRD, the trend does not match the measured magnetic properties at 400 Hz, which may have been affected by other parameters in addition to crystallographic texture.

This paper reports the effects of tensile deformation and annealing conditions on the microstructure and magnetic properties of non-oriented electrical steel. The samples were subjected to tensile strains between 8% and 25% and subsequently annealed in air at temperatures from 700 to 900 °C. The experimental results show that the crystallographic texture of annealed samples depends strongly on the annealing temperature. Fibers textures of type 〈011〉//RD, 〈001〉//ND and 〈111〉//ND, are obtained at temperatures below the Ae 1 . In contrast, annealing at temperatures within the two-phase field region (Ae 1 3 ) promotes the development of [332][ 1 ¯ 1 ¯ 3] and [110][001] textures components. These results are supported by calculations with JMatPro software which show that the Ae 1 and Ae 3 transformation temperatures are 725 and 930 °C, respectively. It was also found that the final recrystallized grain size is inversely proportional to the deformation level imposed before the annealing it means, samples with higher deformation result in smaller grain size. In addition, energy losses in annealed samples are higher for higher levels of deformation, which indicates that grain size is the main microstructural parameter that affects the magnetic behavior of annealed samples.

Commercial NdFeB powders mixed with DyH x nanoparticles are hot pressed and hot deformed into anisotropic magnets by Spark Plasma Sintering (SPS). The hot deformed magnet exhibits strong c -axis crystallographic texture. The coercivity of the magnet doped with 1.0 wt% DyH x is increased by 66.7%, compared with the magnet without DyH x , while the remanence decreases only by 3%. TEM observation shows that there exists a continuous (Nd,Dy) 2 Fe 14 B layer between Nd-rich phase and NdFeB main phase.

In Nd 2 Fe 14 B/α-Fe melt-spun ribbon, P addition is found to be effective for the orientation of c axis of Nd 2 Fe 14 B grains normal to the ribbon plane. A Nd 9.5 Fe 84 B 6.4 P 0.1 melt-spun ribbon with strong crystallographic texture was prepared. The magnets show strong magnetic anisotropy between in and out of the ribbon planes. Large energy product of 190 kJ/m 3 and high remanence of 1.18 T were observed perpendicular to the ribbon plane direction, which are about 46% and 18% higher than those measured in the direction parallel to the ribbon plane direction.

Different thickness (001) textured FePt–X films were fabricated on MgO and SrTiO3 substrates, and the microstructure and magnetic properties of FePt–X films was systematically investigated. The study showed that the substrates with different lattice mismatch resulted in different crystallographic texture and microstructure. The larger mismatch strain with using MgO substrates would cause FePt films to follow the island growth mode, and the negligible mismatch strain with using STO substrate would form continuous film. Doping SiNx and C into FePt films caused the increase of lattice mismatch strain between FePt and MgO/STO, which would induce FePt films to forming island growth. The perpendicular anisotropy of FePt–SiNx–C films grown on MgO substrate was larger than that of using SrTiO3 substrate, which was attributed to the larger strain induced by larger lattice mismatch.

Fabricating anisotropic bulk TbCu7-type RCo7 nanocrystalline magnets is of great significance for their development as high-performance high temperature magnets. In this paper, anisotropic bulk TbCu7-type (Sm0.6Pr0.4)Co7 nanocrystalline magnets have been prepared using high-pressure thermal compression (HPTC). The (Sm0.6Pr0.4)Co7 magnet had a strong (0 0 2) crystallographic texture and a small grain size of ~20 nm, yielding a maximum energy product of (BH)max = 19.5 MGOe. The magnets showed a coercivity temperature coefficient of β = −0.21%/°C from room temperature (RT) to 300 °C, better than that −0.23%/°C of the SmCo7 magnets prepared in the same conditions.

The influence of Nb content on the primary recrystallization microstructure, crystallographic texture and magnetic properties of grain-oriented silicon steel manufactured by low-temperature slab reheating were studied. The results show that the effect of grain refining was enhanced with the increase of Nb content. With the increase of Nb content, the total contents of texture {1 1 1}〈1 1 2〉 and {1 1 4}〈4 8 1〉 in primary recrystallization which are beneficial to the secondary recrystallization increased, but the contents of deviated Goss component and adverse textures with abnormal growth ability in primary recrystallization also increased, which led to the deterioration of magnetic properties. By adding 0.005% Nb, the average size of the primary grain reduced to 23 μm, the content of {1 1 0}〈1 1 2〉 increased slightly and the least deviated Goss nuclei were obtained, therefore the final product had the sharpest {1 1 0}〈0 0 1〉 texture of secondary recrystallization and the best magnetic properties with B800 = 1.873 T , P1.7/50 = 1.21 W/kg.

Heusler alloys demonstrate various effects, such as the ferromagnetic shape memory effect, the magnetocaloric effect, etc. But these alloys are also liable to destruction during multiple cycles of martensitic transformation. In order to increase stability of functional properties of the alloys, thermo-mechanical treatment by various methods is carried out. In this work, a Heusler Ni2.26Mn0.80Ga0.89Si0.05 alloy was subjected to combined deformation processing: multiple isothermal forging and subsequent direct extrusion. The multiple isothermal forging was carried out at 700 °C in 5 upset transitions and a total true degree of deformation of e ≈ 2.42. The extrusion was also carried out at 700 °C with an extrusion ratio of 2:1 (e = 1.39). Analysis of the microstructure shows that, resulting from combined treatment, metallographic and crystallographic textures are formed. The metallographic texture is characterized by coarse grains of approximately 1 mm in length and hundreds of microns in diameter. The coarse grains are in turn surrounded by a layer of fine-grained structure. The crystallographic texture is axial of the 〈1 1 0〉 type. This kind of structure enhances mechanical properties of the alloy. According to the study of thermal expansion anisotropy in the region of martensitic transformation, contribution of the martensitic transformation to the relative change in the length of the extruded sample is 0.13% in the direction, normal to the extrusion axis, and 0.09% - along it. These values are comparable to those observed on Heusler alloys in the as-cast state. Thus, it is found that thermo-mechanical treatment by the combined method allows obtaining a significant amount of thermal expansion anisotropy while remarkably increasing mechanical properties of the material.

We systematically investigated the local crystallographic texture, magnetic domain structure, and the associated magnetic reversal process of different regions, namely fine-grain (FG), coarse-grain (CG), and large-grain (LG) regions in hot-deformed Nd-Fe-B magnets. The FG region possesses the strongest (00 l) texture and plays a dominant role on the magnetic properties. In contrast, the CG region with partially aligned sub-micron grains and the LG region with randomly aligned micro-sized grains exhibit much weaker (00 l) texture, where the reversal magnetic domains primarily nucleate, deteriorating the remanence and the squareness of the demagnetization curve seriously. This finding highlights a new strategy to achieve high energy density in hot-deformed Nd-Fe-B magnets, i.e. maximizing the volume fraction of highly (00 l) textured FG regions and reducing the undesirable CG and LG regions. Our further experiment enhancing the maximum energy product of the magnet from 42.6 to 51.1 MGOe through optimizing the microstructure homogeneity unambiguously demonstrates the general applicability of the strategy.

The aging temperature to improve magnetic properties in Maraging-350 steel (Mar-350) is limited by the onset of austenite reversion. The traditional process of cooling after aging is to remove the piece from the oven and then to air cool it. The purpose of this research was to characterize the reverted austenite and to investigate the effect of cooling below the martensite start temperature ( M s ) on the magnetic properties. The Mar350 samples aged at temperatures above 550 °C, and subsequently cooled in liquid nitrogen presented less austenite than samples cooled in air, resulting in higher magnetization saturation and a lower coercive force. A combination of optical microscopy (OM), X-ray diffraction (XRD) and electron backscatter diffraction (EBSD) techniques were used to characterize the presence of reverted austenite. The crystallographic texture of both martensite and reverted austenite were analyzed. The texture of the reverted austenite coincides with the texture of the parent austenite indicating that a phenomenon of texture memory is present.

The effect of the initial annealing on structure evolution and magnetic properties during the final annealing of a 3.4% Si non-oriented grain steel was evaluated. Half of the samples were submitted to initial annealing at 1030 °C before cold rolling and all samples were subjected to final annealing process at temperatures from 540 °C to 1100 °C. The magnetic induction and core loss in the final samples, the microstructure by optical microscopy and the crystallographic texture by X-ray diffraction and EBSD were evaluated. The results show that the samples without initial annealing presented better magnetic properties than the samples with initial annealing, due to the higher ratio between Eta fiber and Gamma fiber volume fractions (Eta/Gamma ratio) in their structure after final annealing.

Grain-oriented electrical steel containing 6.5 wt% Si is a promising soft magnetic material with very low iron losses for high-frequency applications. However, due to the ordered phases formed in the microstructure, the room-temperature ductility (formability) of this material is extremely low. It is essentially not possible to process this steel by conventional cold rolling. In this study, an Fe-6.5 wt% Si grain-oriented electrical steel was processed through strip casting (also known as twin-roll casting), hot rolling, warm rolling, cold rolling, primary and secondary annealing. The effect of hot rolling reduction rate (12–40%) on the microstructure, crystallographic texture and magnetic properties of the final steel sheets was investigated. The results showed that hot rolling increased the area fraction of the Goss ({1 1 0}〈0 0 1〉) grains, reduced the grain size, and promoted the precipitation of fine second-phase particles. After warm rolling, cold rolling and primary annealing, the recrystallized microstructure was the finest if the hot-rolling reduction rate was the highest (40%). After secondary annealing, the steel with the largest hot rolling reduction rate (40%) showed the most apparent abnormal grain growth, leading to the formation of the Goss texture. As a result, the magnetic flux density and the magnetic Barkhausen noise (MBN) also showed the largest values among all the samples. On the other hand, those with lower hot-rolling reduction rates (12–32%) showed no or less abnormal grain growth during secondary recrystallization, which resulted in lower magnetic flux density and weaker magnetic Barkhausen noise. Increasing the amount of hot rolling reduction was thus able to promote abnormal grain growth during secondary recrystallization, and optimize the magnetic properties of the steel.

The effect of rolling and annealing on the crystallographic texture and the magnetic properties of Fe-2.6% Si non-oriented electric steel during 90% cold rolling and different annealing temperature at (600 °C, 700 °C, 900 °C and 1100 °C) for 60 min and 20 min was analyzed. The 97% hot rolled as received material shows development of alpha and gamma fiber texture affecting on the magnetic properties at rolling and transverse direction. 90% cold rolling with moderate annealing temperature (up to 700 °C) and 60 min annealing time leads to better textures and improved magnetic properties. Due to coarse grained microstructure after annealing, neutron diffractions is an efficient tool for the analysis of Bulk texture of polycrystalline materials, well known for sufficient grain statistics and bulk texture measurement.

In an attempt to differentiate the impact of grain size and crystallographic texture on magnetic properties of non-oriented (NO) electrical steel sheets, samples with different grain sizes and textures were produced and analyzed regarding magnetic flux density B and core loss W. The textures of the NO electrical steel samples could be precisely quantified with the help of elliptical Gaussian distributions. In samples with identical textures, small grain sizes resulted in about 15% higher core loss W than larger grains, whereas grain size only moderately affected the magnetic flux density B. In samples having nearly the same grain size, a correlation of the magneto-crystalline anisotropic properties of B and W with texture was obtained via the anisotropy parameter A ( h → ) . With increasing A ( h → ) a linear decrease of B and a linear increase of W were observed.

M-type barium ferrite (BaM) film is a promising candidate for magnetic recording media and the next-generation high-frequency microwave material. BaM films were fabricated using a chemical solution spin-coating deposition method on (001) plane sapphire. The effect of ethylene glycol (EG) on precursor solution and annealing temperature on microstructure and magnetic properties were investigated. X-ray diffraction showed that strong out-of-plane (001) texture in BaM films can be achieved with adequate EG addition. Films fabricated without EG addition or annealed at lower temperatures showed partial hematite secondary phase. The epitaxial formation of hematite secondary phase on sapphire substrate was confirmed by the X-ray diffraction φ-scan technique. Magnetic measurements showed out-of-plane anisotropy in BaM films. The crystallographic texture and magnetic anisotropy of the films are related to the film microstructure.

The paper presents new investigations of high magnetic field (HMF) effects on phase and structural transformations as well as historical development of the problem. The regularities of structure evolution under simultaneous action of heat treatment and high magnetic field have been studied on different alloys. It was shown, that magnetic field can affect thermodynamics and kinetics of transformation, which results in changes in the phase composition, crystallographic texture, rate of transformation, morphology of precipitating particles, and other effects. The observed phenomena strongly depend on magnetic properties of phases involved into transformation such as magnetic moment, magnetic susceptibility, magneto-crystalline anisotropy, magnetostriction. The review comprises the main results of modern researches into the influence of magnetic field of tens Tesla on the phase and structural transformations in materials with different type of magnetic ordering. Further research directions of HMF effect on the thermally activated transformations are proposed.

This paper describes a method of producing circumferentially oriented magnetic hard composites (bonded magnets). This means that the directions of easy magnetization of the magnetically hard particles contained in the magnet are perpendicular to the radius and to the axis of the cylindrical sample (parallel to the direction tangential to the surface of the cylinder). Tests were carried out on two magnetically hard materials (Nd-Fe-B and barium ferrite) with two different volumes of the solid phase in the slurry. The bonded magnets were produced by the centrifugal casting of the slurry in a constant magnetic field. The obtained shapes, in the form of cylinders, possessed a well compacted hard magnetic layer, with a thickness depending on the powder content in the slurry. In all cases, the remanence of the obtained samples was the highest in the circumferential direction, i.e. perpendicular to the longitudinal section of the cylinder. X-ray investigations revealed that the samples obtained have a crystallographic texture. A model of phenomena occurring during centrifugal casting of slurry in a magnetic field was proposed, which explains the structure of the obtained materials is shaped.

In material models for the finite-element simulation of electrical machines and the preceding magnetic measurements, the magnetic anisotropy of non-grain oriented electrical steel is usually considered in an oversimplified way, if at all. The magnetization behavior between rolling and transverse direction is not linear and varies with magnetic polarization, a relation that comes in addition to the complexity of the effect. In this paper, the magnetization anisotropy of five industrial non-grain oriented electrical steels is measured with a 1-D single-sheet-tester. The results are evaluated and correlated to the crystallographic texture of the studied materials. An approach to model magnetization curves at 50 Hz in arbitrary directions of the sheet plane is presented. The model is parametrized by measured magnetization curves along three different spatial directions and by macro-texture data in form of an orientation distribution function. This approach leads to a model that replicates the crossing of magnetization curves of different orientations with adequate quantitative accuracy for the application in FE magnetic field simulations.

The magnetism and the microstructure of Ni2MnGa alloys, processed by the first time by twin roller melt spinning at tangential wheel speeds of 10 m/s (V10), 15 m/s (V15) and 20 m/s (V20) are investigated. At room temperature, the major phase in the as-cast alloys is the cubic L21 Ni2MnGa ordered austenitic phase, with a lattice parameter only ~0.1% larger than the tabulated value. The order domain size in the austenitic phase decreases from (40±1) nm in samples V10 to (19±1) nm in V20. Mn(S,Se) small precipitates are also found uniformly embedded in the ribbons with mean size of (26±2) nm (V10) and (7±2) nm (V20), exhibiting a definite orientation relation with the austenitic matrix, P // a. The as-cast alloys transform to an intermediate cubic phase I at about 220K-230K depending on the quenching rate and to a martensitic phase at about 130K. The high temperature austenitic phase and the low temperature martensitic phase are ferromagnetic; in both cases the saturation polarization is lower in samples quenched at higher rates. The demagnetization curves measured from saturation in the martensitic state show two marked steps: a first one for positive fields in V15 and V10 (~46 mT) and a larger second one for relatively large inverse fields (~130-250 mT) in all the samples. These steps are likely to arise from a demagnetization mechanism involving a field induced twin boundary motion in the few martensite variants selected by the crystallographic texture and the quenched stresses in the ribbons. Fil: Pozo Lopez, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina Fil: Condo, Adriana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Bariloche). División Física de Metales; Argentina Fil: Giordano, Rafael Nicolás. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina Fil: Urreta, Silvia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina Fil: Haberkorn, Nestor Fabian. Comision Nacional de Energía Atómica. Gerencia de Área Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Bariloche). División Física de Metales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Winkler, Elin Lilian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Bariloche). División Resonancias Magnéticas; Argentina Fil: Fabietti, Luis Maria Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina

Magnetic phase evolution, crystallographic texture, microstructure and magnetic properties of Fe–28Cr–15Co–3.5Mo–1.8Ti alloy have been investigated by X-ray diffractometry, scanning transmission electron microscopy and magnetometry techniques as a function of processing conditions. Heat treatment conditions for obtaining optimum textural, microstructural and magnetic properties have been established by the experimentations. The Goss {110}〈001〉 and cube type {001}〈010〉 textures have been developed in an optimal treated Fe–28Cr–15Co–3.5Mo–1.8Ti magnets. The coercive force in Fe–28Cr–15Co–3.5Mo–1.8Ti magnets depends critically on the shape anisotropy of rod-like Fe Co Ti-rich α 1 particles and remanence on the alignment and elongation of α 1 particles parallel to applied magnetic field 〈100〉 directions. The optimum magnetic properties obtained in Fe–28Cr–15Co–3.5Mo–1.8Ti alloy are intrinsic coercive force, i H c , of 78.8 kA/m (990 Oe), remanence, B r of 1.12 T (11.2 kG) and energy product, (BH) max of 52.5 kJ/m 3 (6.5 MGOe). The development of Fe–28Cr–15Co–3.5Mo–1.8Ti magnets as well as characterization of texture, microstructural and magnetic properties in the current study would be helpful in designing the new Fe–Cr–Co–Mo based magnets suitable for scientific and technological applications.

The effect of thermomechanical processing on the formation of shear bands and on the magnetic properties of a 3.0 wt% silicon non-oriented steel was investigated by hot rolling samples with different thicknesses at different temperatures, in order to obtain a variation in hot band grain size and cold strain. All the samples were processed in a single-stage cold rolling and finally annealed at 1020 1C. It was found that the increase of the hot band grain size decreases the g fiber volume fraction and increases the Z fiber volume fraction after the final annealing. The increase of the cold strain strongly contributed to this result. A good combination of intense generation of shear bands, and proper crystallographic texture, due to higher nucleation of grains with favorable orientations to magnetization in these bands, can be obtained for the samples hot rolled at 1000 and 1120 1C and submitted to cold strain of 64.3% and 72.2% respectively. However the best combination of B50, W15/60 and mr can be obtained by hot rolling the samples at 1000 1C to the thickness of 1.4 mm, corresponding to 64.3% of cold strain.

In order to quantify the impact of crystallographic texture on the variation of magnetic flux density B(α) in non-oriented electrical steel, two sheet samples with identical chemical composition were produced in a way to achieve different textures. A correlation between the values of B(α) and an anisotropy parameter A ( h → ) obtained from the sheet textures was established. In turn, this correlation was used to compute in-plane variations of B(α) for various single crystal orientations as well as various characteristic polycrystal texture components. Since non-oriented electrical steel is mainly used in applications with changing directions of magnetization the planar magnetic flux density B ¯ , which averages the in-plane variation of B(α), is an important measure of the overall magnetizing ability. A high planar magnetic flux density B ¯ is achieved by increasing texture components with their {0 0 1} poles close to the sheet normal direction, perpendicular to the sheet plane, while suppressing texture components whose {0 0 1} poles deviate from the normal direction by more than 30°.

We have studied the effects of the initial stages of the annealing on magnetic tunnel junctions with MgO barriers and CoFeB electrodes. We report changes in the resistance–voltage characteristics and tunneling magnetoresistance for patterned transport junctions, and correlate these with the observed changes in the structural and magnetic interface morphologies determined by soft X-ray resonant magnetic scattering from sheet films from the same wafer. An important feature of our experiment was that all measurements were carried out within the soft X-ray diffractometer on samples from the same wafer subjected to simultaneous annealing cycles, so that our magnetotransport and scattering data are directly comparable. The as-grown junction showed a tunneling magnetoresistance ratio of 5.5%, and a specific barrier resistance of 85.6 k Ω μ m 2 . A 200 ∘ C anneal for 1 h resulted in a small rise in barrier resistance and magnetoresistance coupled with a smoothing of the magnetic interfaces, consistent with the healing of barrier defects and removal of tunneling hot-spots. A subsequent 300 ∘ C anneal for a further hour resulted in further smoothing, and a rise in the magnetoresistance ratio to 72%, and a much weaker dependence of the parallel state resistance upon voltage bias, indicating the development of ( 0 0 1 ) crystallographic texture in the electrodes. Annealing to 325 ∘ C yielded a further decrease in magnetic interface width (the quadrature sum of roughness and intermixing length scales). The reduction in interface width for Co species occurred at higher temperatures than for Fe throughout the experiments.