Spin Disordered Resistivity of the Heusler Ni2MnGa-based Alloys
J. Kamaráda, J. Kaštil a, F. Albertini b, S. Fabbrici b and Z. Arnold a
aInstitute of Physics, ASCR, v.v.i., Na Slovance 2, 182 21 Prague 8, Czech Republic
bIMEM CNR, Parco Area delle Scienze 37/A, I-43124 Parma, Italy
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Electrical resistivity of the selected Heusler off-stoichiometric (NiCo)2Mn(GaIn) alloys was studied in a wide range of temperature and magnetic field. A step-like change of resistivity (Δρ ≈24 μΩcm) was detected in the off-stoichiometric Ni1.85Mn1.21Ga0.94 alloy at temperature of martensitic structural transition. This Δρ is much more significant than one in the stoichiometric Ni2MnGa alloy. In the case of the off-stoichiometric (NiCo)2Mn(GaIn) alloys, an enormous change of resistivity, Δρ ≈ 200 μΩcm, accompanies the structural transition. Simultaneously, the maximum of the spin disordered resistivity ρsd(T) of austenite phase of the alloys is slightly dependent on composition of the alloy and vary from ≈30 μΩcm up to ≈45 μΩcm, in good agreement with theoretical calculations. Due to high sensitivity of the structural transition temperature of the alloys to magnetic field, the very pronounced magnetoresistance effects have been observed in the studied alloys.

DOI: 10.12693/APhysPolA.131.1072
PACS numbers: 75.50.Cc, 81.30.Kf, 72.15.Eb, 75.47.De