Mechanomagnetic spectroscopy of ferromagnetic shape memory alloys

Abstract

We have used a recently designed mechanomagnetic spectroscopy technique to study the inverse magnetoelastic effect (stress-induced magnetization) in ferromagnetic materials simultaneously with their elastic and anelastic properties. Special attention has been paid to ferromagnetic shape memory alloys. Application of mechanomagnetic spectroscopy technique allows one to study the stress-induced motion of elastic (by means of the anelasticity measurements) and magnetic domain boundaries (through the detection of the stress-induced magnetization). The experimental technique is based on the piezoelectric ultrasonic composite oscillator technique with an additional magnetic channel, enabling to register the induction, produced by the strain of a ferromagnetic sample, down to 10 −10 T. Examples of application of this new technique are given, which include observation of a temperature–magnetic field domain wherein magnetoelastic coupling demonstrates variations of sign and analysis of magnetic domain wall dynamics in polycrystalline ferromagnetic martensites.