Reduction of Photographic Noise*

Magnetic domains have been observed in material with composition close to 77% Ni-14% Fe-5% Cu-4% Mo for both vanishingly small and finite values of K1, the first anisotropy constant. An initial permeability of 70 × 103 was obtained. The domain structure was governed by random internal stresses in the material and no clear dependence on grain orientation or K1 was established. The application of tensile stress caused a reduction in permeability and an increase in eddy current loss. Bar-type domains are formed whose spacing diminishes with increasing stress. The results are shown to be in agreement with theory based on the μ* effect.

Section: 3 the Magneto-optic Apparatusmentioning

confidence: 92%

Section: 3 the Magneto-optic Apparatusmentioning

confidence: 99%

Magnetic domains and high permeability in Ni-Fe-Cu-Mo alloys

Preece¹,

Thompson²

1971

“…However, owing to the thermal grooving, there was still a large amount of scattered light in the reflected beam. To overcome the effects of this all photographs were subjected to the 'double-negative' treatment of Fowler and Fryer (1954).…”

Section: Methodsmentioning

confidence: 99%

Ferromagnetic domain structures in 65% nickel-35% iron alloys

Jackson

Lee

1969

The Kerr magneto-optic effect has been used to observe domain structures on rings of 65% nickel-35% iron after annealing just below the Curie point with and without an external field being present. In general the observations are consistent with the Néel-Taniguchi theory of pair orientation, but measurements of wall movement in the constant-permeability region of the hysteresis loop of the baked alloy do not agree with predictions of theory.

“…The variation of the relief effect with angle is more pronounced in figure 4(b) in which an abnormally irregular section of wall in the same sample is shown. In this case a double negative technique was applied to reduce the background variations (Fowler and Fryer 1954). Generally, domain photographs are processed to obtain maximum contrast but this would be inappropriate in the present work where the full tonal range is required.…”

Section: Magneto-optic Investigations Of Wall Structuresmentioning

confidence: 99%

An investigation of saw-tooth domain walls in Ni/Fe/Co films

Sanders

Jones

Collins

1977

Head-on domains having saw-tooth wall configurations in Ni/Fe/Co films are discussed in relation to the existing theoretical models. The existence of Neel tails within such wall structures as previously proposed is supported and discussed with respect to: (a) direct magneto-optic observations and measurements, and (b) a comparison of the predicted saw-tooch amplitude and angles with the observed values. A large number of films were investigated and the wall angles were found to be dependent upon the ratio of the coercivity to anisotropy field, Hc/Hk, as predicted in the Neel tail model, whilst the saw-tooth amplitude was determined predominantly by the coercivity. Effective wall widths of the order of 100 mu m have been observed in 0.14 mu m thick 80/17/3 Ni/Fe/Co films.