Hamburg 2001 – scientific programme

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DS: Dünne Schichten

DS 24: Spezielle Schichten II

DS 24.2: Talk

Thursday, March 29, 2001, 15:00–15:15, S 13/14

Structural and magnetic properties of thin films and multilayers of the Heusler alloys Cu₂MnAl, Co₂MnSn and Co₂MnSi — •Uwe Geiersbach, Andre Bergmann, and Kurt Westerholt — Institut für Experimentalphysik IV Ruhr Universität Bochum 44780 Bochum Germany

We have prepared thin films of the intermetallic Heusler compounds Cu₂MnAl, Co₂MnSn and Co₂MnSi by RF sputtering on MgO- and sapphire substrates. The Co-based Heusler alloys provide examples of ferromagnetic metals with a high spin polarization at the Fermi level, making them very attractive for applications in GMR and TMR elements. Cu₂MnAl can be grown epitaxially with (100)-orientation on MgO (100) and (110)-orientation on Al₂O₃ a-plane. Co₂MnSn and Co₂MnSi need V or Au seed layers to induce epitaxial growth. Using V and Au as nonmagnetic interlayers we were able to grow high quality multilayers of the Heusler compounds. Whereas the Cu₂MnAl-compound tends to grow in the disorderd B2-type structure with a corresponding reduction of the ferromagnetic magnetisation, the Co-based alloys grow in the ordered L2₁ structure and preserve the full magnetisation.