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J.W. Wieberdink

Bio: J.W. Wieberdink is an academic researcher. The author has contributed to research in topics: Magnetoresistance & Magnetization. The author has an hindex of 1, co-authored 1 publications receiving 7 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the Stoner-Wohlfarth single-domain model is used to describe the systematic error of an angle detector using multilayers with different orientations of their anisotropy axes.
Abstract: The anisotropic magnetoresistance effect of Permalloy (Ni/sub 0.82/Fe/sub 0.18/) is used in a contactless angle detector. The uniaxial magnetic anisotropy in a Permalloy thin film causes a difference between the direction of magnetization and the magnetic field direction. This leads to a systematic error in the angle detector output. The effects of uniaxial magnetic anisotropy can be reduced by using Permalloy multilayers with different orientations of their anisotropy axes. A double layer with mutually perpendicular anisotropy axes is found to be sufficient for application in an angle detector. The Stoner-Wohlfarth single-domain model is used to describe the systematic error of an angle detector using multilayers. >

7 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, an introduction to the theory of the anisotropic magnetoresistance effect in ferromagnetic thin films is given, ending in a treatment of the minimalization of the free energy which is the result of the intrinsic and extrinsic anisotropies of the thin-film structure.
Abstract: An introduction to the theory of the anisotropic magnetoresistance effect in ferromagnetic thin films is given, ending in a treatment of the minimalization of the free energy which is the result of the intrinsic and extrinsic anisotropies of the thin-film structure. The anisotropic magnetoresistance effect in long strips is reviewed. Attention is given to problems like the formation of domains and measures like biasing and linearization. The paper concludes with a description of some applications which are being developed by the authors: (1) an analyser for the stray field of recording heads; (2) a sensitive magnetometer; (3) an accurate absolute angle detector; and (4) an absolute (linear) position detector.

23 citations

Journal ArticleDOI
01 May 1965-Nature
TL;DR: Prutton as mentioned in this paper described thin ferromagnetic films as a "thin Ferromagnetic film" and showed how to make them work well in the real world. Pp. viii + 269.
Abstract: Thin Ferromagnetic Films By M. Prutton. Pp. viii + 269. (London: Butterworth and Co. (Publishers), Ltd., 1964.) 80s.

15 citations

Journal ArticleDOI
TL;DR: In this paper, the AMR effect of single-domain film-resistors is used for magnetic field and linear/angular displacement sensing, and a pseudo-super-paramagnetic behavior is observed.
Abstract: The AMR effect of single-domain film-resistors is being widely used for magnetic field and linear/angular displacement sensing. However, several constrains attributed to the repeatability of magnetization orientation limit the accuracy of such devices. There is a trade-off between device sensitivity and measurement repeatability; the anisotropy field HK affects both parameters in an inverse manner. To overcome such problems we propose the employment of AMR film-resistors as fluxgate devices. Using a rotating magnetic field vector as excitation, the anisotropic magnetoresistance material is kept continuously in saturation and a pseudo-super-paramagnetic behaviour is observed. Thus, the signal noise coming from Barkhausen jumps can be narrowed down to zero.

12 citations

Journal ArticleDOI
TL;DR: In this article, the effect of variation in the thickness of ion assisted ion beam sputtered MgO spacer layer deposited at oxygen ion assisted energy of 50 eV on the extent of magnetic coupling of NiFe and CoFe layers in Si/NiFe(10 nm)/Mg(1.5
Abstract: The effect of variation in the thickness of ion assisted ion beam sputtered MgO spacer layer deposited at oxygen ion assisted energy of 50 eV on the extent of magnetic coupling of NiFe and CoFe layers in Si/NiFe(10 nm)/Mg(1 nm)/MgO(2,4,6 nm)/CoFe(10 nm) sandwich structure is investigated. At MgO spacer layer thickness of 4 nm, the separate reversal of magnetizations of the two ferromagnetic layers is observed in the hystresis loop recorded along easy direction. This results in a 3.5 Oe wide plateau like region during magnetization reversal, which became 4.5 Oe at 6 nm thin MgO. At 2 nm thin MgO, the absence of plateau during magnetization reversal region revealed ferromagnetic coupling between the two ferromagnetic layers, which is understood to arise due to the growth of very thin and low density (1.22 gm/cc) MgO spacer layer, indicating the presence of pinholes as revealed by x-ray reflectometry. After vaccum annealing (200 °C/1 h), the plateau region for 4 and 6 nm thin MgO case decreased to 1.5 Oe and...

11 citations

Journal ArticleDOI
TL;DR: In this article, the magnetic properties of sputtered permalloy (Ni80Fe20) multilayers grown changing the anisotropy direction 90° in successive layers were reported.
Abstract: This work reports the magnetic properties of sputtered permalloy (Ni80Fe20) multilayers grown changing the anisotropy direction 90° in successive layers. Magnetic measurements show how the saturating field can be controlled by the thickness ratio between different anisotropy layers and how the coercive field is reduced increasing the number of layers. The linearity of the hysteresis loop is also improved when increasing the number of layers. Magnetic measurements are compared to simulations based on a Stoner-Wolfarth magnetization rotation mechanism.

9 citations