Structural properties and magnetic interactions in martensitic Ni-Mn-Sb alloys

Abstract

We study the structural and magnetic properties of Heusler based Ni₅₀Mn_50−x Sb _x in the composition range 5.0 ≤ x ≤ 25.0. The cubic phase is preserved in the range 17.0 ≤ x ≤ 25.0, and the presence of martensitic transformations are found in alloys with x ≤ 15.0. In a critical composition range 12.5 ≤ x ≤ 10.0, the magnetic coupling in both austenitic and martensitic phases is paramagnetic, however, the presence of antiferromagnetic short-range correlations is observed in both phases. We discuss the consequences of these correlations on the behavior of the magnetic moment with respect to electronic properties.

Keywords:

• Heusler alloys
• magnetization
• neutron polarization analysis
• magnetic correlations
• phase diagrams

Acknowledgements

This work was supported by Deutsche Forschungsgemeinschaft (No. SPP1239), CICyT (Spain) project MAT2007-61200, and the Institut Laue-Langevin, Grenoble.