Magnetic domain structure in a metamagnetic shape memory alloy Ni45Co5Mn36.7In13.3

Correlation between the magnetism and the martensitic transformation in Ni45Co5Mn36.7In13.3 has been revealed by electron holography and Lorentz microscopy. The parent phase exhibits typical closure magnetic domains due to low magnetocrystalline anisotropy. Upon cooling, the magnetic flux density of the parent phase monotonically increases, while the magnetic domain structure remains almost unchanged; in other words, the effect of premartensitic lattice modulation appears to be small in this alloy. The magnetic domains disappear immediately when the martensitic transformation occurs.