Structural and magnetic properties of He+ irradiated Co2MnSi Heusler alloys

Iman Abdallah (1) , Nicolas Ratel-Ramond (1) , C. Magen (2, 3) , Béatrice Pécassou (1) , Robin Cours (1) , Alexandre Arnoult (4) , Marc Respaud (5) , Jean-François Bobo (6) , Gérard Benassayag (6) , Etienne Snoeck (7) , Nicolas Biziere (6)

1 CEMES - Centre d'élaboration de matériaux et d'études structurales
2 Departamento de Física de la Materia Condensada
3 INA - Instituto de Nanociencia de Aragón [Saragoza, España]
4 LAAS-TEAM - Service Techniques et Équipements Appliqués à la Microélectronique
5 LPCNO - Laboratoire de physique et chimie des nano-objets
6 CEMES-MEM - Matériaux et dispositifs pour l'Electronique et le Magnétisme
7 CEMES-I3EM - Interférométrie, In situ et Instrumentation pour la Microscopie Electronique

We have investigated the atomic disorder induced by a 150 keV He+ ion irradiation in a 40 nmthick Co2MnSi Heusler alloy. Disorder parameters on each atomic site are deduced from normal and anomalous X-ray diffraction measurements with Co and CuKasources. While the film grows mainly in the L21 phase with inclusion of B2 grains, we observe an increase of both theMn-Si and Co-Mn exchanges with the ion fluence. HAADF-STEM analysis demonstrates that the increase inMn-Si disorder corresponds to a growing size of the B2 grains while the Co-Mnexchange is accounted for a D03 disorder type in the L21 matrix. These structural modifications are shown to decrease the average magnetization of the alloy, which is due to D03 disorder and local defects induced by irradiation.

Mots clés: Heusler Alloys; Structure; X-ray diffraction; HAADF-STEM

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Iman Abdallah, Nicolas Ratel-Ramond, C. Magen, Béatrice Pécassou, Robin Cours, et al.. Structural and magnetic properties of He+ irradiated Co2MnSi Heusler alloys. Materials Research Express, 2016, 3 (4), pp.046101. ⟨10.1088/2053-1591/3/4/046101⟩. ⟨hal-01718887⟩