scholarly journals Enhanced Reversible Magnetic-Field-Induced Strain in Ni-Mn-Ga Alloy

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2017
Author(s):  
Pingping Wu ◽  
Yongfeng Liang
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Tensile Stress ◽  
Field Model ◽  
Magnetic Domain ◽  
Phase Field Model ◽  
Martensite Variant ◽  
Ferromagnetic Domain ◽  
Biaxial Tensile Stress ◽  
Variant Structure

A phase-field model was developed to simulate the ferromagnetic domain structure and martensite variant microstructure of Ni-Mn-Ga shape-memory alloy. The evolution of reversible magnetic-field-induced strain (MFIS) and associated magnetic domain/martensite variant structure were modeled under an external magnetic field. It was found that MFIS increased significantly from 0.2% to 0.28% as the temperature increased from 265 K to 285 K. In addition, compressive pre-stress efficiently enhanced the MFIS of the alloy, while tensile stress reduced MFIS. Furthermore, it was proved that there was possibility of achieving similar enhancement of MFIS by replacing compressive stress with perpendicular biaxial tensile stress. The results revealed that the residual variant induced by stress plays an important role in the reversible MFIS effect.

scholarly journals A kinetic Monte Carlo study for stripe-like magnetic domains in ferrimagnetic thin films

Open Physics ◽  
2013 ◽  
Vol 11 (4) ◽  
Author(s):  
Botond Tyukodi ◽  
Ioan-Augustin Chioar ◽  
Zoltán Néda
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
External Magnetic Field ◽  
Kinetic Monte Carlo ◽  
Magnetic Domain ◽  
Hysteresis Loops ◽  
Monte Carlo Study ◽  
Driving Frequency ◽  
Magnetic Domains ◽  
Equilibrium Limit

AbstractThe topology and dynamics of stripe-like magnetic domains obtained in a ferrimagnetic garnet subjected to a time-dependent external magnetic field is studied experimentally and theoretically. Experiments are performed on a commercially available magnetic bubble apparatus, allowing the observation of the time-evolution of the magnetic domain structure. The system is modeled by a meso-scale Ising-type lattice model. Exchange and dipolar interactions between the spins, and interaction of the spins with the external magnetic field are considered. The model is investigated by kinetic Monte Carlo simulations with time-varying transition rates. In the limit of low temperatures the elaborated model leads to a magnetic domain topology and dynamics that is similar to the ones observed in the experiments. In the highly non-equilibrium limit with a high driving frequency the model reproduces the experimentally recorded hysteresis loops as well.

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