J. Sievert

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Papers by J. Sievert

International comparison on SST and Epstein measurements in grain-oriented Fe-Si sheet steel

by J. Sievert, K. Gramm, S. Norman, and chaoyong Wang

International Journal of Applied Electromagnetics and Mechanics, 2015

Rotational Dynamic Magnetostriction of Si-Fe Sheet

ABSTRACT Rotational dynamic magnetostriction (RDM) was measured as a function of rotating magneti... more ABSTRACT Rotational dynamic magnetostriction (RDM) was measured as a function of rotating magnetic flux density for nonoriented and grain-oriented silicon steel sheets under various magnetizaiton conditions. The rotational dynamic magnetostriction was measured using two-dimensional strain gauges, which provide x- and y-directional outputs. The RDM in silicon steel sheet is larger than the alternating magnetostriction in the rolled direction.

Magnetic measurements on electrical steels using Epstein and SST methods Summary report of the Euromet comparison

Magnetic Measurements on Electrical Steels using Epstein and SST Methods–EUROMET Comparison between Standard Laboratories

Magnetic Phase Diagram of the Reentrant Spin Glass System (Fe0.65Ni0.35)1−xMnx in External Magnetic Fields

Physica Status Solidi (a), 1993

Dedicated to Professor Dr. CHRISTOPH SCHWINK on the occasion of his 65th birthday On the alloy sy... more Dedicated to Professor Dr. CHRISTOPH SCHWINK on the occasion of his 65th birthday On the alloy system (Feo,6sNio,3s)~-xMnx (0 5 x 5 0.30) magnetization studies using a Faraday balance and a SQUID magnetometer are performed. The temperature range examined was from 4.4 up to 300 K and the external magnetic field is varied from 0.01 up to 5.5 Tin some cases. Using an objective criterion characteristic temperatures are determined: the Curie temperature T,, the temperature of the maximum value of magnetization T,, and the temperature rim of the onset of the collapse into the spin glass state. Several magnetic phases are found as paramagnetism, ferromagnetism, concentrated spin glass, and antiferromagnetism, and we observed the ferromagnct c-) spin glass and antiferromagnct ++ spin glass recntrant transitions. The transition temperatures between these phascs are collected in magnetic phase diagrams regarding different external magnetic fields.

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Summary report: Measurements on electrical sheet steels

Metrologia, 1999

Anomalous anisotropy and rotational magnetic properties of amorphous sheet

Journal of Magnetism and Magnetic Materials, 1992

ABSTRACT We have studied the two-dimensional magnetic properties of amorphous sheets by consideri... more ABSTRACT We have studied the two-dimensional magnetic properties of amorphous sheets by considering the relation between field strength vector H and flux density vector B. The measurement results show an anomalous anisotropy in high induction level. This differs entirely from the anisotropy of rolled sheets observed in low field. The new type of anisotropy appeared in a direction of 45° to the rolling direction.

The measurement of magnetic properties of amorphous strips at higher frequencies using a yoke system

Journal of Magnetism and Magnetic Materials, 1992

For the determination of the nower losses and other relevant quantities of metallic glass ribbons... more For the determination of the nower losses and other relevant quantities of metallic glass ribbons, a yoke set-up with various coil systems has been cc,rstructed. A digital oscilloscope and a microcomputer were used for the measurement. Results obtained using the H-coi! m~:thod and by determining the field strength from the magnetizing current are in agreement within 5% in the frequency range up to 100 kHz.

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Coercivity meter with earth's magnetic field compensation

Journal of Magnetism and Magnetic Materials, 1996

Magnetic phase diagram of the reentrant spin glass system (Fe0.65Ni0.35)1−xMnx

Journal of Magnetism and Magnetic Materials, 1992

We performed magnetization studies on the alloy system (F%,sNi~.3.s) ~ , Mn, 111 _< x _< 11.311) ... more We performed magnetization studies on the alloy system (F%,sNi~.3.s) ~ , Mn, 111 _< x _< 11.311) using a Faraday balance and a SQUID magnetometer. The temperature r'mge examined was from 4.5 up to 2811 K and the external magnetic field ~va,, varied from I1.111 up to 5.5 T in some cases. Using an objective criterion we determined characteristic temperatures for different manganese ,,oncentrations: the Curie temperature 7"~.. the temperature of the maximum of magnetization 7~,, and the temperature Tim of the onset of the collapse into the spin glass state. These temperatures are collected in at phase diagram versus manganese concentration.

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Comparison of a single strip tester and Epstein frame measurements

Journal of Magnetism and Magnetic Materials, 1982

We have measured the magnetic properties of different sorts of magnetic steel sheet using a singl... more

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$Research paper thumbnail of Order and magnetic properties of Fe89−xMn11Alx alloys: magnetization measurements and X-ray diffraction$

Order and magnetic properties of Fe89−xMn11Alx alloys: magnetization measurements and X-ray diffraction

Journal of Alloys and Compounds, 2004

We report experiments performed on a series of fourteen Fe 89−x Mn 11 Al x alloys in the concentr... more We report experiments performed on a series of fourteen Fe 89−x Mn 11 Al x alloys in the concentration range 2 at.% < x < 40 at.% examining structure, degree of long range order and the magnetic properties. We found the type of long range order is concentration dependent, changing from A2, crossing a DO 3 region up to B2. The structural order found in this system is of great influence on the magnetic moments of the Fe atoms. Therefore the wide concentration range of the alloys investigated allowed us to observe the change from ferromagnetism via a region of re-entrance from ferromagnetism to spin glass till antiferromagnetism. In the re-entrant concentration range, we derive the magnetic field dependence on characteristic temperatures for the alloys Fe 62 Mn 11 Al 27 and Fe 59 Mn 11 Al 30 and demonstrate that the latter is very near the critical concentration where the Curie temperature and the freezing temperature of the re-entrant spin glass become equal. (H. Bremers), J.hesse@tu-bs.de (J. Hesse). systematically changing the aluminium concentration. Former work in the (Fe 65 Ni 35 ) 1−x Mn x system [20] has shown, that 11 at.% of manganese is sufficient to see re-entrant spin glass behaviour in that system. For this we have chosen the series of Fe 89−x Mn 11 Al x alloys varying x between 2 and 40 at.% in small steps. We observed that increasing the aluminium concentration, the alloys change their behaviour from ferromagnetic to antiferromagnetic, crossing regions with re-entrant spin glass behaviour. In regions of aluminium concentrations higher than 30 at.%, we found the onset of antiferromagnetism at temperatures below 18 and 37 K respectively.

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Distribution of two-dimensional magnetic properties in three-phase induction motor model core

IEEE Transactions on Magnetics, 1996

ABSTRACT Improving material characteristics and optimizing technical designs have been studied fr... more ABSTRACT Improving material characteristics and optimizing technical designs have been studied from the standpoint of efficiency improvement of electrical machinery and apparatus. Unfortunately, the local magnetic properties in the actual core are still not fully understood. On the other hand, the concert of the two-dimensional (vector) description of the magnetic properties was developed. It means that the description of the relationship between the magnetic field strength vector H and the magnetic flux density vector B which are usually not parallel but have the phase angle, by means of a permeability tensor. In general, the magnetic quantities show not only the non-linearity of amplitude but also a spatially different angular position (we call it spatial-phase angle). Therefore, the local magnetic quantities in an actual constructed core should be measured as vector quantities. This paper presents the local magnetic quantities in a three-phase induction motor model core, which were measured with the two-dimensional measurement sensor.

On the calibration of vibrating sample magnetometers with the help of nickel reference samples

IEEE Transactions on Magnetics, 1993

The temperature dependence and the influence of the sample shape on the field dependence of the m... more The temperature dependence and the influence of the sample shape on the field dependence of the magnetization of nickel samples are investigated with a vibrating sample magnetometer. Three different Ni materials have a temperature coefficient of 5×10-4/K. The field dependence can be described by a sum of a term proportional to the field H and a second one proportional to H-2. The relative deviations between experimental and fitted magnetization values in the field range 0.5 T&les;μ0 H&les;8 T are less than 10 -3 and show no systematic change wit the field. Only the nonlinear term shows a strong dependence on the sample shape and is important for fields μ0 H&les;2 T

On the calibration of magnetometers having electromagnets with the help of cylindrical nickel reference samples

IEEE Transactions on Magnetics, 1990

In order to avoid the great effort required in tracing back the indication of a magnetometer dire... more In order to avoid the great effort required in tracing back the indication of a magnetometer directly to SI units, reference samples are usually applied. In the case of magnetometers with iron cores, this procedure is accompanied by several problems influencing the accuracy. The problems connected with the measurement of the properties of the reference sample in the standards laboratory

Two-dimensional magnetic properties of silicon steel sheet subjected to a rotating field

by J. Sievert and T. Todaka

IEEE Transactions on Magnetics, 1993

... in the given direction, but cannot be said to reflect the overall properties or behavior of t... more

Domain structure of a 5% Si-Fe single crystal with Néel orientation

IEEE Transactions on Magnetics, 1984

Physikalisch-Technische B u n d e s a n s t a l t , B u n d e s a l l e e 100 , 64 3300 Braunschw... more Physikalisch-Technische B u n d e s a n s t a l t , B u n d e s a l l e e 100 , 64 3300 Braunschweig , FRG **Vacuumschmelze, 6 4 5 0 Hanau, FRG A b s t r a c t : The i n f l u e n c e o f d i f f e r e n t t h e r m o m a g n e t i c p r ep a r a t o r y t r e a t m e n t s o f a 5 % S i -F e s i n g l e c r y st a l w i t h N Q e l o r i e n t a t i o n on t h e b e h a v i o u r o f the magnetic domain s t r u c t u r e was i n v e s t i g a t e d by means o f t h e Kerr magneto-opt&c e f f e c t . The c r y s t a l w a s cooled down from 600 C t o room t e m p e r a t u r e a p p l y i n g d i f f e r e n t k i n d s o f magn e t i c f i e l d s , w h i c h l e a d s t o v a r i o u s k i n d s o f behaviour of the domain widths depending on t h e a c t u a l m a g n e t i c f i e l d s t r e n g t h

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Numerical analysis and experimental study of the error of magnetic field strength measurements with single sheet testers

IEEE Transactions on Magnetics, 1986

The error of the measurement of t h e magnetic field strength w i t h a single sheet tester has b... more The error of the measurement of t h e magnetic field strength w i t h a single sheet tester has been studied. Two different methods, determin a t i o n by means of field sensing coils ( 1 ) and from the magnetizing c u r r e n t ( 2 ) I have been compared. The errors of methods ( I ) and ( 2 ) werecalculated by the finite element method ( F E M ) , different parameters having been varied, and method ( 2 ) was additionally studied experimentally. SSTs with wound yokes and stacked yokes were considered. The r e s u l t s will help to decide whether the more cornplic a t e d and more accurate H coil method or t h e easier to handler b u t less accurate rn,c.method is chosen.

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Rotational power loss of silicon steel sheet

IEEE Transactions on Magnetics, 1990

Rotational power losses have been measured on nonoriented grain-oriented silicon steel sheets und... more Rotational power losses have been measured on nonoriented grain-oriented silicon steel sheets under different rotational flux conditions. Several methods have been proposed for this purpose. Among these, a method based on the measurement of the field quantities B x, By, Hx, and Hy seems to be the most convenient as far as the preparation of the test specimen is concerned.

European intercomparison of measurements on permanent magnets

IEEE Transactions on Magnetics, 1993

The results of a European intercomparison of measurements on permanent magnetic materials are rep... more The results of a European intercomparison of measurements on permanent magnetic materials are reported. The intercomparison consists of two parts, i.e., measurements on cylindrical specimens of AlNiCo and NdFeB in a closed magnetic circuit; and measurements on spherical specimens of NdFeB in an open magnetic circuit using vibrating sample or SQUID magnetometers. Together with the other specimens, nickel reference specimens are circulated for calibration purposes. The results of the intercomparisons are complex, but in general the agreement obtained is quite good. A comparison of the two parts shows in Hc, HcB and (BH)max are considerable, which can be interpreted in the light of the aging of the NdFeB spherical specimens due to the preparation process

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