COMPARISON OF MAGNETIC AND STRUCTURAL PROPERTIES OF RAPIDLY QUENCHED BULK AND RIBBON Ni₂MnGa HEUSLER ALLOYS

Zuzana Vargova – Tomas Ryba – Sergej Ilkovic – Marian Reiffers –
Vladimir Komanicky – Robert Gyepes – Rastislav Varga

   We are dealing with the magnetic and structural properties of Ni2MnGa Heusler alloys prepared by different rapid quench-ing methods. They allow a fast production of relatively large amount of alloy by arc melting (bulk, rod) or by melt spinning methods (ribbon).The SEM studies reveal slight variation of chemical composition for rod and ribbons. However, X-ray dif-fraction confirms the same single B2 crystalline phase at room temperature in both cases. Temperature dependence of magneti-zation reveals different structural transition temperatures for rods and ribbons. Moreover, different anisotropies have been in-duced during production reflecting the different temperature gradient during quenching for rod (which shows no preferred easy axis) and ribbon (which shows easy magnetization axis parallel to the ribbon surface).

Keywords: Heusler alloy, magnetocaloric effect, rapid quenching method

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