The investigation of longitudinal acoustic waves in Heusler Ni53Mn25Ga22 alloy crystal with coupled magnetostructural transition
|Yuri A. Kuzavko|
The Polesie Agrarian Ecological Institute of the National Academy of Science of Belarus (PAEI), Brest 224000, Belarus
This alloy has reversible thermoelastic martensite transitions. The process of a return to parent shape is coupled with a reveversible transition of a deformed martensite (D4h) phase into a high-temperature austenitic (Oh) one. For our crystall the lattice parameters are a=b=0.7753 nm, c=0.6598 nm, as for Ni2MnGa a=b=0.5920 nm, c=0.5566 nm at D4h phase, a=0.5825 nm at Oh.
We have studied experimentally the temperature dependences of the ultrasound speed and amplitude of pulse signals my means of digital measuring equipments.
The presence of a soft transverse mode TA2 takes place for the alloy . It propagates along directions  and related with accession to zero of the elasticity constant c`=(c11-c12)/2. The theory was designed for investigated effects consisting the linear and nonlinear magnetoacoustical ones.
Presentation: Oral at E-MRS Fall Meeting 2008, Symposium C, by Yuri A. Kuzavko
See On-line Journal of E-MRS Fall Meeting 2008
Submitted: 2008-05-30 10:29 Revised: 2009-06-07 00:48
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