Opeil, C. P.Mihaila, B.Schulze, R. K.Mañosa, LluísPlanes Vila, AntoniHults, W. L.Fisher, R. A.Riseborough, P. S.Littlewood, P. B.Smith, J. L.Lashley, J. C.2019-06-272019-06-272008-04-230031-9007https://hdl.handle.net/2445/135979Ultraviolet-photoemission (UPS) measurements and supporting specific-heat, thermal-expansion, resistivity, and magnetic-moment measurements are reported for the magnetic shape-memory alloy Ni 2 MnGa over the temperature range 100 < T < 250     K . All measurements detect clear signatures of the premartensitic transition ( T PM ∼ 247     K ) and the martensitic transition ( T M ∼ 196     K ). Temperature-dependent UPS shows a dramatic depletion of states (pseudogap) at T PM located 0.3 eV below the Fermi energy. First-principles electronic structure calculations show that the peak observed at 0.3 eV in the UPS spectra for T > T PM is due to the Ni d minority-spin electrons. Below T M this peak disappears, resulting in an enhanced density of states at energies around 0.8 eV. This enhancement reflects Ni d and Mn d electronic contributions to the majority-spin density of states.4 p.application/pdfeng(c) American Physical Society, 2008Física de partículesExperimentsParticle physicsExperimentsinfo:eu-repo/semantics/article6003592019-06-27info:eu-repo/semantics/openAccess