Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 49: POSTER II

MA 49.35: Poster

Donnerstag, 19. März 2015, 15:00–18:00, Poster A

Influence of the composition on the martensitic transformation and structure of epitaxial Ni-(Co-)Mn-Sn thin films. — •Daniel Kucza, Niclas Teichert, and Andreas Hütten — Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, Germany

Due to its promising magentocaloric properties, structure, transformation temperatures, thermal hysteresis and surface morphology (AFM) of epitaxial Ni-Co-Mn-Sn thin films were examined. Measured with different compositions these Heusler alloys show a structural transition carried out from the low temperature martensitic to the high temperature austenitic phase. The compositions of the four alloys is set between Ni₅₀Co₀Mn₃₆Sn₁₃ and Ni₄₇Co₃Mn₃₇Sn₁₂. The films itself are prepared by magnetron co-sputtering from elemental targets on MgO(001) substrates.

The structure and surface morphology of the films is determined by X-ray diffraction and atomic force microscopy. To study the transformation temperatures and thermal hysteresis, several temperature dependent X-ray diffractions of a complete circle of cooling and heating of each sample are carried out.

The results show a widening of the thermal hysteresis with a change in the composition in case of increasing Co content.