Title:
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Combined Experimental and Theoretical Investigation of the Premartensitic Transition in Ni2 MnGa
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Author:
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Opeil, C. P.; Mihaila, B.; Schulze, R. K.; Mañosa, Lluís; Planes Vila, Antoni; Hults, W. L.; Fisher, R. A.; Riseborough, P. S.; Littlewood, P. B.; Smith, J. L.; Lashley, J. C.
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Other authors:
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Universitat de Barcelona |
Abstract:
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Ultraviolet-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. |
Subject(s):
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-Física de partícules -Experiments -Particle physics -Experiments |
Rights:
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(c) American Physical Society, 2008
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Document type:
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Article Article - Published version |
Published by:
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American Physical Society
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