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Superparamagnetismus und Oberflächenanisotropie in dünnen Schichten. I. Drehmomentenmessungen an sehr dünnen Permalloyschichten
Author(s) -
Hemschik H.
Publication year - 1969
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.19694780110
Subject(s) - permalloy , perpendicular , materials science , condensed matter physics , coupling (piping) , torr , magnetization , anisotropy , torque , amplitude , nuclear magnetic resonance , magnetic field , physics , optics , composite material , geometry , mathematics , quantum mechanics , thermodynamics
Permalloy films in the thickness range 5…40 Å are evaporated at about 10 −5 Torr and investigated by the torque method. In the thinner films there is a marked easy direction perpendicular to the film plane. Since just in these films the magnetization is thermally very instable, it is difficult to saturate the torque amplitude. The inverse shape anisotropy is evidently due to a surface effect. The maximum torque depends on the measuring field in a manner, which is typical for an anisotropy of the intergrain coupling; hence this coupling is essentially due to magnetostatic forces.