Abstract
Ni2MnGa and Co2FeGe0.5Ga0.5 are promising members of Heusler alloys family because of their aplication potential as micropumps [1] or actuators [2] (Ni2MnGa) and spintronics [3] (Co2FeGe0.5Ga0.5). Their key properties are connected to well ordered low-temperature phase L21.
Contrary to that high-temperature ordering B2 corresponds to mixing of atoms at individual sites in the unit cell. The presence of these to types of ordering can be observed by x-ray diffraction.
Due to different symmetry and centration of unit cells all diffractions with all indices odd are extincted in B2 ordering. Contrary, diffractions with all indices odd and also with all indices even corresponding to L21 ordering are present.
Therefore, with the measurement of ratio of integrated intesities we can determine the partial content of L21 vs B2 ordering in our samples. But there is neccessity to include all angular dependent corrections. [1] A.
R. Smith, A.
Saren, J. Järvinen, K.
Ullakko, Characterization of a high resolution solid state micropump that can be integrated into microfluidic systems, Microfluidics and Nanofluidics (2015) 18:1255-1263, doi: 10.1007/s10404-014-1524-6 [2] A. Hobza, C.
L. Patrick, K.
Ullakko, N. Rafla, P.
Lindquist, P. Müllner, Sensing strain with Ni-Mn-Ga, Sensors and Actuators A 269 (2018) 137-144, doi: 10.1016/j.sna.2017.11.002 [3] Ikhtiar, S.
Kasai, Y. K.
Takahashi, T. Furubayashi, S.
Mitani, and K. Hono, Temperature dependence of magneto-transport properties in Co2Fe(Ga0.5Ge0.5)/Cu lateral spin valves, Applied Physics Letters 108, 062401 (2016); doi: 10.1063/1.4941549