Characterization of Softmagnetic Thin Layers using Barkhausen Noise Microscopy

MRS Proceedings ◽

10.1557/proc-674-u1.5 ◽

2001 ◽

Vol 674 ◽

Author(s):

Jochen Hoffmann ◽

Norbert Meyendorf ◽

Iris Altpeter

Keyword(s):

Residual Stresses ◽

Magnetic Hysteresis ◽

Ferromagnetic Material ◽

Heat Treatment Condition ◽

Thin Layers ◽

Barkhausen Noise ◽

Layer System ◽

Structure Thickness ◽

Inductive Sensors

ABSTRACTFerromagnetic materials are essential for data recording devices. For inductive or magnetoresistive (MR) sensors softmagnetic thin layer systems are used. Optimal performance of these layers requires homogeneous magnetic properties, especially a pronounced uniaxial magnetic anisotropy. Furthermore, microstructural imperfections and residual stresses influence the magnetic structure in the layer system.Barkhausen Noise Microscopy enables the characterization of such thin layers. By cycling the magnetic hysteresis of ferromagnetic material electrical voltages (the Barkhausen noise) are induced in an inductive sensor. Miniaturization of the sensor and the scanning probe technique provides resolution down to few micrometers. Two materials were examined in terms of their structure, thickness, residual stresses and heat treatment condition: Sendust, used in inductive sensors and nanocrystalline NiFe, used in MR-sensors. In quality correlations to Barkhausen noise parameters were found. For representative sample a quantification of residual stress distribution could be established employing X-ray stress analysis.

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Characterization of the Residual Stresses in Plastically Deformed Ferrite-Martensite Steels Using Barkhausen Noise Measurements

Materials Science Forum ◽

10.4028/www.scientific.net/msf.500-501.655 ◽

2005 ◽

Vol 500-501 ◽

pp. 655-662 ◽

Cited By ~ 1

Author(s):

Xavier Kleber ◽

Aurélie Hug-Amalric ◽

Jacques Merlin

Keyword(s):

Plastic Deformation ◽

Tensile Stress ◽

Residual Stresses ◽

Barkhausen Noise ◽

Opposite Behavior ◽

Noise Measurements ◽

Two Phases ◽

Noise Signature ◽

Compressive Residual Stresses

In this work, we show that the measurement of the Barkhausen noise allows the residual stresses in each of the two phases of ferrite-martensite steels to be characterized. We have first studied the effect of a tensile and a compressive stress on the Barkhausen noise signature. We observed that for a ferrite-martensite steel, the application of a tensile stress increases the Barkhausen activity of the martensite and ferrite phases, whereas a compressive one reduces it. In a second time, we induced residual stresses by applying a plastic deformation to ferrite-martensite steels. After a tensile plastic deformation, we observed that (i) compressive residual stresses appear in ferrite, and (ii) tensile residual stresses appear in martensite. An opposite behavior is observed after a compressive plastic deformation. These results show that the Barkhausen noise measurement makes it possible to highlight in a nondestructive way the distribution of the stresses in each of the two phases of a ferrite-martensite steel. This result could be used to characterize industrial Dual- Phases steels that are plastically deformed during mechanical processes.

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Characterization of the Residual Stresses in Plastically Deformed Ferrite-Martensite Steels Using Barkhausen Noise Measurements

Materials Science Forum - Microalloying for New Steel Processes and Applications ◽

10.4028/0-87849-981-4.655 ◽

2005 ◽

pp. 655-662 ◽

Cited By ~ 1

Author(s):

Xavier Kleber ◽

Aurélie Hug-Amalric ◽

Jaques Merlin

Keyword(s):

Residual Stresses ◽

Barkhausen Noise ◽

Noise Measurements

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Characterization of Residual Stresses and Microstructural by Technique of Magnetic Barkhausen Noise of API 5L X80 Steel Heat Treatment

Materials Science Forum ◽

10.4028/www.scientific.net/msf.869.556 ◽

2016 ◽

Vol 869 ◽

pp. 556-561 ◽

Cited By ~ 1

Author(s):

Sandro Rosa Correa ◽

Marcos Flavio de Campos ◽

C.J. Marcelo ◽

José Adilson de Castro ◽

Maria Cindra Fonseca ◽

...

Keyword(s):

Residual Stresses ◽

Barkhausen Noise ◽

Magnetic Barkhausen Noise ◽

X Ray Diffraction ◽

X80 Steel ◽

Work Samples ◽

Non Destructive ◽

Different Levels ◽

Steel Heat

Residual stresses typically are generated during the manufacturing process of mechanical components. The non-destructive techniques are quite sensitive to these residual stresses, and to microstructural changes resulting from thermal cycling. In this work, samples of API 5L X80 steel were exposed to several conditions of cooling, under water, air and oil, thus obtaining different microstructures and different levels of residual stresses. The residual stress measurements were made using the methods of Magnetic Barkhausen Noise and X-ray diffraction.

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Azimuthal Anchoring Strength in Photopatterned Alignment of a Nematic

Crystals ◽

10.3390/cryst11060675 ◽

2021 ◽

Vol 11 (6) ◽

pp. 675

Author(s):

H. Nilanthi Padmini ◽

Mojtaba Rajabi ◽

Sergij V. Shiyanovskii ◽

Oleg D. Lavrentovich

Keyword(s):

Liquid Crystal ◽

Point Defects ◽

Elastic Energy ◽

Separation Distance ◽

Thin Layers ◽

Uv Exposure ◽

Surface Anchoring ◽

Anchoring Strength ◽

Spatially Varying

Spatially-varying director fields have become an important part of research and development in liquid crystals. Characterization of the anchoring strength associated with a spatially-varying director is difficult, since the methods developed for a uniform alignment are seldom applicable. Here we characterize the strength of azimuthal surface anchoring produced by the photoalignment technique based on plasmonic metamsaks. The measurements used photopatterned arrays of topological point defects of strength +1 and −1 in thin layers of a nematic liquid crystal. The integer-strength defects split into pairs of half-integer defects with lower elastic energy. The separation distance between the split pair is limited by the azimuthal surface anchoring, which allows one to determine the strength of the latter. The strength of the azimuthal anchoring is proportional to the UV exposure time during the photoalignment of the azobenzene layer.

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Time-Response-Histogram-Based Feature of Magnetic Barkhausen Noise for Material Characterization Considering Influences of Grain and Grain Boundary under In Situ Tensile Test

Sensors ◽

10.3390/s21072350 ◽

2021 ◽

Vol 21 (7) ◽

pp. 2350

Author(s):

Jia Liu ◽

Guiyun Tian ◽

Bin Gao ◽

Kun Zeng ◽

Yongbing Xu ◽

...

Keyword(s):

Grain Boundary ◽

Tensile Stress ◽

Material Properties ◽

Ferromagnetic Material ◽

Silicon Steel ◽

Time Response ◽

Barkhausen Noise ◽

Time Interval ◽

Magnetic Barkhausen Noise

Stress is the crucial factor of ferromagnetic material failure origin. However, the nondestructive test methods to analyze the ferromagnetic material properties’ inhomogeneity on the microscopic scale with stress have not been obtained so far. In this study, magnetic Barkhausen noise (MBN) signals on different silicon steel sheet locations under in situ tensile tests were detected by a high-spatial-resolution magnetic probe. The domain-wall (DW) motion, grain, and grain boundary were detected using a magneto-optical Kerr (MOKE) image. The time characteristic of DW motion and MBN signals on different locations was varied during elastic deformation. Therefore, a time-response histogram is proposed in this work to show different DW motions inside the grain and around the grain boundary under low tensile stress. In order to separate the variation of magnetic properties affected by the grain and grain boundary under low tensile stress corresponding to MBN excitation, time-division was carried out to extract the root-mean-square (RMS), mean, and peak in the optimized time interval. The time-response histogram of MBN evaluated the silicon steel sheet’s inhomogeneous material properties, and provided a theoretical and experimental reference for ferromagnetic material properties under stress.

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Characterization of Residual Stresses in Composites

Fundamentals of Metal-Matrix Composites ◽

10.1016/b978-0-08-052371-2.50008-0 ◽

1993 ◽

pp. 61-80 ◽

Cited By ~ 4

Author(s):

MARK A.M. BOURKE ◽

JOYCE A. GOLDSTONE ◽

MICHAEL G. STOUT ◽

ALAN NEEDLEMAN

Keyword(s):

Residual Stresses

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MECHANICAL CHARACTERIZATION OF MATERIALS AND DIAGNOSIS OF STRUCTURES BY INVERSE ANALYSES: SOME INNOVATIVE PROCEDURES AND APPLICATIONS

International Journal of Computational Methods ◽

10.1142/s0219876213430020 ◽

2014 ◽

Vol 11 (03) ◽

pp. 1343002 ◽

Cited By ~ 11

Author(s):

GIULIO MAIER ◽

VLADIMIR BULJAK ◽

TOMASZ GARBOWSKI ◽

GIUSEPPE COCCHETTI ◽

GIORGIO NOVATI

Keyword(s):

Structural Analysis ◽

Digital Image Correlation ◽

Residual Stresses ◽

Mechanical Characterization ◽

Image Correlation ◽

Alkali Silica Reaction ◽

Compression Tests ◽

Material Models ◽

Characterization Of Materials

A survey is presented herein of some recent research contributions to the methodology of inverse structural analysis based on statical tests for diagnosis of possibly damaged structures and for mechanical characterization of materials in diverse industrial environments. The following issues are briefly considered: identifications of parameters in material models and of residual stresses on the basis of indentation experiments; mechanical characterization of free-foils and laminates by cruciform and compression tests and digital image correlation measurements; diagnosis, both superficially and in depth, of concrete dams, possibly affected by alkali-silica-reaction or otherwise damaged.

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