Preparation and structural properties of thin films and multilayers of the Heusler compounds Cu2MnAl, Co2MnSn, Co2MnSi and Co2MnGe

TL;DR

This study reports on the fabrication and structural analysis of thin films and multilayers of various Heusler compounds, revealing their growth orientations, interface qualities, and magnetic properties, with implications for spintronic applications.

Contribution

It demonstrates the epitaxial growth of Cu2MnAl and the necessity of seedlayers for Co-based Heusler alloys, along with multilayer fabrication with smooth interfaces and analysis of their magnetic disorder.

Findings

Cu2MnAl grows epitaxially with specific orientations on MgO and Al2O3.

Co-based Heusler alloys require seedlayers for textured growth.

Multilayers exhibit reduced magnetization due to disorder and intermixing.

Abstract

We report on the preparation of thin films and multilayers of the intermetallic Heusler compound CuMnAl, Co2MnSn, Co2MnSi and Co2MnGe by rf-sputtering on MgO and Al2O3 substrates. Cu2MnAl can be grown epitaxially with (100)-orientation on MgO (100) and in (110)-orientation on Al2O3 a-plane. The Co based Heusler alloys need metallic seedlayers to induce high quality textured growth. We also have prepared multilayers with smooth interfaces by combining the Heusler compounds with Au and V. An analysis of the ferromagnetic saturation magnetization of the films indicates that the Cu2MnAl-compound tends to grow in the disordered B2-type structure whereas the Co-based Heusler alloy thin films grow in the ordered L21 structure. All multilayers with thin layers of the Heusler compounds exhibit a definitely reduced ferromagnetic magnetization indicating substantial disorder and intermixing at the interfaces.