Martensitic transition in strong magnetic field and external stress in quaternary ferromagnetic shape memory alloy Ni-Mn-Fe-Ga
|Victor V. Koledov 2, Rostislav M. Grechishkin 4, Vladimir V. Khovailo 2, Vladimir G. Shavrov 2, V. G. Pushin 1, A V. Korolyov 1, N I. Kourov 1, Evgeniy P. Krasnoperov , Alexandra A. Tulaikova 2, Vasiliy D. Buchelnikov 3, Sergey V. Taskaev 3, Chengbao Jiang 5|
1. Russian Academy of Sciences, Ural Division, Institute of Metal Physics, 18 S.Kovalevskaya str., GSP-170, Ekaterinburg 620219, Russian Federation
Ferromagnetic shape memory alloys of the Ni-Mn-Ga family demonstrate a very spectacular illustration of magnetoelastic coupling. In these alloys the thermoelastic martensitic transition may occur in the ferromagnetic state. As a result giant magnetoinduced deformations up to several percents due to martensite domain boundaries movement  and magnetically controlled shape memory effect due to martensitic transition  can be observed in single- and polycrystals, respectively. The behavior of martensitic transition under the action of external field and stress is of extreme impotence in view of possible applications of polycrystalline alloys in sensor and actuator technology.
The aim of the present work is to study experimentally and theoretically the martensitic transition in polycrystalline Ni2.14Mn0.81Fe0.05Ga under the action of external uniaxial compressive stresses up to 40 MPa and magnetic fields up to 5 T. The measurements of low-field magnetic susceptibility near martensitic transition reveal that external stress tends to shift the martensitic transition hysteretic loop to a higher temperature region and to smoother the transition, widening the transition loop. Strong magnetic field up to 5 T shifts the hysteretic loop to higher temperatures without a pronounced deformation of the loop. In situ optical observations show the evolution of martensitic and ferromagnetic domains structure caused by the external stress. The theoretical and experimental results are in good agreement.
This work is supported by RFBR (Grants 03-02-17443, 04-02-81058, 03-02-39006).
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Presentation: oral at E-MRS Fall Meeting 2005, Symposium C, by Victor V. Koledov
See On-line Journal of E-MRS Fall Meeting 2005
Submitted: 2005-05-19 09:34 Revised: 2009-06-07 00:44