Controlling the magnetic coercivity by heat treatment in Heusler Ni-Mn-Ga(-B) single crystals exhibiting magnetic shape memory effect


Magnetic shape memory materials can exhibit novel interesting magnetomechanical effects if they show simultaneously large mobility of twin boundaries and magnetic coercivity. We found a method how to enlarge the magnetic coercivity by a controlled heat treatment of material. Simultaneously we explained the mechanism of magnetic coercivity, which depends on the density of antiphase boundaries in the material. The finding enables further studies of new unique magnetomechanical effects in magnetic shape memory alloys.

Magnetic domains and antiphase boundaries in Ni-Mn-Ga(-B) single crystal
Antiphase boundaries and corresponding magnetic microstuctures observed in slowly and rapidly cooled magnetic shape memory single crystal and corresponding measurement of magnetic coercivity and its temperature dependence.

Contact: Ing. Ladislav Straka, D.Sc. (Tech.)
Collaborating institutions: Charles University, Faculty of Mathematics and Physics