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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Structural and magnetization changes at high temperature in Co50Mn30In20 alloy.
Mst Nazmunnahar1, Lorena González, Maxim Ilyn
1Dpto. Física de Materiales, UPV/EHU, Apdo. 1072, 20080 San Sebastián, Spain.
Journal of Nanoscience and Nanotechnology
|October 6, 2012
Summary
This study characterizes Co50Mn30In20 alloy ribbons, revealing the Heusler phase Co2MnIn in annealed samples. Annealing affects magnetic properties and recrystallization temperatures.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Metallurgy
Background:
- Co-based Heusler alloys are investigated for their magnetic properties.
- Melt-spun ribbons offer unique microstructural characteristics.
- Understanding phase transitions and magnetic ordering is crucial for alloy development.
Purpose of the Study:
- To characterize the microstructure and magnetic properties of Co50Mn30In20 alloy ribbons.
- To compare the as-cast and annealed states of the alloy.
- To investigate the influence of annealing on magnetic ordering temperatures and phase transitions.
Main Methods:
- Differential Scanning Calorimetry (DSC) for thermal analysis.
- X-ray Diffraction (XRD) for phase identification and crystallite size.
- Scanning Electron Microscopy (SEM) for microstructural analysis.
- Magnetic measurements (hysteresis loop, magnetization) from 1.8 K to 1000 K.
Main Results:
- Annealed ribbons exhibit the Heusler phase Co2MnIn with crystallites around 35 nm.
- The Curie temperature (Tc) for the annealed sample is 520 K, lower than the as-cast ribbon's 550 K.
- An abrupt magnetization change at 840 K in the annealed sample coincides with the recrystallization temperature.
Conclusions:
- Annealing transforms the Co50Mn30In20 alloy into the Co2MnIn Heusler phase.
- The annealing process influences the magnetic ordering temperature and induces a significant magnetization change linked to recrystallization.
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