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XVII.—The Superposition of Mechanical Vibrations (Electric Oscillations) upon Magnetisation, and Conversely, in Iron, Steel, and Nickel
Published online by Cambridge University Press: 06 July 2012
Extract
That mechanical vibrations affect magnetisation has long been known. The simple experiment of hammering an iron rod (Gilbert) in the earth's magnetic field needs only to be mentioned
About twenty years ago Ewing published investigations upon the effects of vibrations on magnetism. These have been summarised in his subsequent work, Magnetic Induction in Iron and other Metals. He states (§ 84, 3rd ed.) that the “influence of vibrations and mechanical disturbances generally” “may be succinctly described by saying that vibration lessens those differences of magnetic condition to which hysteresis gives rise. Thus, if we tap a piece of iron during the application and removal of a magnetising force, we find at each stage of the application that tapping increases the susceptibility, and at each stage of the removal it reduces the retentiveness.”
- Type
- Research Article
- Information
- Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 45 , Issue 2 , 1907 , pp. 491 - 517
- Copyright
- Copyright © Royal Society of Edinburgh 1907
References
page 491 note * Phil. Trans., 1885, p. 564.
page 492 note * “Notes on the Effect of Electric Oscillations (co-directional and transverse) on the Magnetic Properties of Iron,” Proc. R.S.E., vol. xxvi. p. 33, 1905Google Scholar.
page 495 note * This process tends to preserve the symmetry of the loops with reference to the origin.
page 501 note * Fig. VIII. is one of the earlier experiments, and a thread was not introduced between the lever and the nickel wire under test. These observations have been repeated with this alteration, and the larger loop ought to be more sheared over than shown in this figure. The coercive force remains the same, the residual magnetisation is reduced to within 10 C.G.S. units of the dotted loop, and the value of H is increased to 1·25. These corrections give the values of R and B at the cyclic extreme the same as in fig. V. for the same value of field. The increase of permeability and residual magnetisation is due to a minute torsional stress imparted to the nickel wire when no thread is introduced. The two smaller loops with and without vibrations remain exactly as shown, as also fig. XI., p. 503. The experimental results, therefore, relative to coercive force and hysteresis loss, remain as stated in the following section.
page 507 note * Magnetic Induction in Iron, Ewing, 3rd ed., p. 248; Jour. Coll. Science Imp. Univ. Japan, vol. ii. p. 304.
page 508 note * “Note on Heusler's Magnetic Alloy,” Proc. Roy. Soc., vol. lxxvii., Series A, p. 256.
page 513 note * Magnetic Induction in Iron, 3rd ed., p. 181 (Wiedemann).
page 514 note * “Notes on the Effect of Electric Oscillations on Magnetism,” L. H. Walter, Electrician, May 5, 1905.
page 515 note * Phil. Mag., August 1906; Electrician, August 24, 1906.