NMR and the antiferromagnetic crystal phase regions in rapidly quenched ribbons and in alloys of the type $Cu-Mn-Al$

TL;DR

This paper investigates the magnetic resonance properties of antiferromagnetic crystal phase regions in rapidly quenched Cu-Mn-Al ribbons, focusing on the coexistence of different magnetic clusters and the effects of nanostructuring.

Contribution

It provides new insights into the magnetic resonance behavior of antiferromagnetic regions with long-range order in Cu-Mn-Al ribbons, expanding understanding beyond Mn clusters.

Findings

Antiferromagnetic and ferromagnetic Mn clusters coexist without long-range order.

Nanostructuring improves magnetic and mechanical properties.

Long-range ordered antiferromagnetic regions may occur in ribbons.

Abstract

It was shown that anomalous resistivity behavior of the $Cu-Mn-Al$ ribbons is explained by the s-d interaction between conduction electrons and the clustered Mn atoms. While nuclear magnetic resonance measurements show the antiferromagnetic and ferromagnetic clusters of Mn atom coexisting without long-range order, it is an interesting problem to study magnetic resonance properties also for the antiferromagnetic crystal phase regions (which have long-range order for larger regions) and which may also occur in these ribbons. The Heusler Type $Cu-Mn-Al$ Alloy has a composition half way between $Cu_{2}MnAl$ and $Cu_{3}Al$. Electron microscopy of the premartensitic $\beta Cu-Zn-Al$ alloy has shown that the $\beta Cu-Zn-Al$ alloy quenched from high temperature has the electron diffraction patterns of this alloy well explained by the model with the existence of small particles with an orthorhombic structure. It was noted that an important aspect of improvement in the material properties is to create a nanostructured state in matrix, which has significant advantages in magnetic and mechanical characteristics in contrast to the bulk materials in crystalline or amorphous state. It is an interesting problem to study magnetic resonance properties not only for the Mn atoms and clusters without long-range order but also for the antiferromagnetic crystal phase regions (which have long-range order for larger regions) which may also occur in ribbons. This is the aim of our paper.