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Updated: Jul 8, 2025
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Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing
Published on: December 3, 2013
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Defect induced ferromagnetism in Mn3Ga.
S V Malik1, E T Dias1, P D Babu2
1School of Physical and Applied Sciences, Goa University, Goa 403206, India.
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|December 12, 2023
Summary
Researchers discovered kinetic arrest in Ni-substituted Mn3Ga alloys, linked to a defect phase transition. This phenomenon, observed for the first time in a compound, arises from the interaction between antiferromagnetic and ferromagnetic phases.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Magnetism
Background:
- Manganese-gallium (Mn-Ga) alloys exhibit complex magnetic properties.
- Ni substitution in Mn-Ga can induce ferromagnetism within an antiferromagnetic matrix.
Purpose of the Study:
- To investigate the origin of ferromagnetism and kinetic arrest in Ni-substituted Mn-Ga alloys.
- To understand the role of local structural defects and phase transitions.
Main Methods:
- Systematic study of crystal structure, local structure, and magnetic properties.
- Analysis of Mn3-xNixGa alloys (x=0, 0.25) using techniques like field cooling and temper annealing.
Main Results:
- Ferromagnetism in Mn2.75Ni0.25Ga originates from segregated Heusler-type environments around Ni.
- Temper annealing leads to the formation of a ferromagnetic Ni-Mn-Ga Heusler phase.
- Exchange bias and kinetic arrest at room temperature are observed due to the interaction between antiferromagnetic and ferromagnetic phases.
Conclusions:
- The first-order transition of an embedded defect phase is responsible for the observed kinetic arrest.
- The interaction between the antiferromagnetic host and ferromagnetic defect phase drives exchange bias.
- This study provides novel insights into kinetic arrest mechanisms in magnetic materials.
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