Martensitic transition, ferrimagnetism and Fermi surface nesting in Mn2NiGaS. R. Barman1, S. Banik1, A. K. Shukla1, C. Kamal2 and Aparna Chakrabarti2
1 UGC-DAE Consortium for Scientific Research - Indore, 452017, Madhya Pradesh, India
2 Raja Ramanna Centre for Advanced Technology - Indore, 452013, Madhya Pradesh, India
received 7 August 2007; accepted in final form 5 October 2007; published December 2007
published online 30 October 2007
The electronic structure of Mn2NiGa has been studied using density functional theory and photoemission spectroscopy. The lower-temperature tetragonal martensitic phase with c/a = 1.25 is more stable compared to the higher-temperature austenitic phase. Mn2NiGa is ferrimagnetic in both phases. The calculated valence band spectrum, the optimized lattice constants and the magnetic moments are in good agreement with experiment. The majority-spin Fermi surface (FS) expands in the martensitic phase, while the minority-spin FS shrinks. FS nesting indicates occurrence of phonon softening and modulation in the martensitic phase.
71.20.Be - Transition metals and alloys.
71.18.+y - Fermi surface: calculations and measurements; effective mass, g factor.
81.30.Kf - Martensitic transformations.
© Europhysics Letters Association 2007