Magnetic, magnetoelastic and dynamical properties of martensitic Heusler alloys - Ab initio and semi-empiric simulations of structural changes of magnetic shape memory systems by external magnetic fields

• Applicant: Professor Dr. Peter Entel (†)
• Subject Area: Materials Science
• Term: from 2006 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 28319882

First-principles calcutations have been used to investigate chemical trends in the structural instability of the high-symmetry cubic structure for a selected set of Heusler compounds X2YZ (X = Fe, Co, Ni, Cu; Y = Mn, Fe Co; Z = Al, Ga, Ge, In, Sn). Preliminary investigations of the role of the valence-electron-to-atom ratio e/a have shown systematic trends in the interatomic force constant, which is found to be an indicator of the structural (martensitic) instability.In this project, we will continue these ab initio investigations by calculating the structural, electronic, magnetic and electron-phonon properties, mainly concentrating on the new magnetic shape memory systems Ni-Mn-In, Ni-Mn-Sn, Ni-Mn-Sb and Ni-Mn-(Ga-In). A recent study of Ni2MnIn has shown that the effect of an external magnetic field on the microstructure at an atomic level can well be taken care of in the ab initio calculations by using the fixed-spin moment method.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1239: Modification of Microstructure and Shape of Solid Materials by External Magnetic Fields