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Updated: Dec 13, 2025
08:55
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
8.8K
Structural-transition-driven antiferromagnetic to spin-glass transition in Cd-Mg-Tb 1/1 approximants
Farid Labib1, Daisuke Okuyama1, Nobuhisa Fujita1
1Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Sendai 980-8577, Japan.
Summary
Increasing magnesium in Cd-Mg-Tb alloys induces an antiferromagnetic to spin-glass transition. This magnetic shift correlates with suppressed superlattice ordering and disordered tetrahedra, impacting quasicrystal properties.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Magnetism
Background:
- Icosahedral quasicrystals and their approximants exhibit complex magnetic behaviors.
- Ternary alloys like Cd-Mg-Tb provide a tunable system to study magnetic transitions.
- Understanding magnetic ordering in these systems is crucial for their technological applications.
Purpose of the Study:
- To investigate the magnetic susceptibility of Cd-Mg-Tb alloys as a function of Mg concentration.
- To correlate magnetic transitions with structural ordering and disorder in quasicrystal approximants.
- To elucidate the origins of the observed antiferromagnetic to spin-glass-like transition.
Main Methods:
- Magnetic susceptibility measurements across a range of temperatures and Mg concentrations.
- Transmission electron microscopy (TEM) for structural analysis and superlattice ordering.
- Analysis of chemical and orientational disorder within the alloy system.
Main Results:
- An antiferromagnetic (AFM) to spin-glass (SG)-like transition was observed with increasing Mg content.
- TEM revealed a correlation between the magnetic transition and the suppression of monoclinic superlattice ordering.
- This suppression was linked to the orientation of Cd4 tetrahedra at temperatures above 100 K.
Conclusions:
- The AFM to SG-like magnetic transition is driven by a combination of chemical disorder (Cd/Mg substitution) and orientational disorder of Cd4 tetrahedra.
- Structural disorder, particularly in the orientation of tetrahedra, plays a significant role in modulating magnetic properties in these quasicrystal approximants.
- The findings offer insights into the relationship between structure and magnetism in complex alloy systems.
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