Method of Measuring the Magnetoelastic Coupling Constants of Cylindrical Magnetic Films
- 1 March 1965
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 36 (3), 966-967
- https://doi.org/10.1063/1.1714280
Abstract
The magnetoelastic energy of a anisotropic film with an axis of symmetry is Bαα12ε112+ Bβα22ε22+ 2Bγα1α2ε12, where the B's are magnetoelastic coupling constants, the α's are direction cosines of the magnetization direction, and the ε's are strains. For a film with an easy axis in the circumferential direction (labeled 1), the effect of applying a tension in the axial direction (labeled 2) and introducing a strain ε22 is to change the uniaxial anisotropy field Hk. The B's are related to this change by Bβ+σBα = ΔHkM/(2ε22), where M is the magnetization and σρ is Poisson's ratio of the wire substrate. The effect of twisting the wire and introducing a strain ε12 is to rotate the easy direction through an angle φ. For small φ, Bγ is related to this skew angle by Bγ=‐MHkφ/(2ε12). For an isotropic film the B's are equal. Measurements have been made on a variety of Permalloy films, some with positive and some with negative magnetostriction, electroplated upon 5‐mil wire. If it is assumed that Bβ=Bα, Bβ is generally found to be larger than Bγ, and not unexpectedly the anisotropy of B is larger in films with large Hk.Keywords
This publication has 3 references indexed in Scilit:
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- Measurements of skew, dispersion, and creep in plated wiresIEEE Transactions on Communication and Electronics, 1964
- Physical Theory of Ferromagnetic DomainsReviews of Modern Physics, 1949