Tunable structural and magnetic properties of chemically synthesized dual-phase Co2NiGa nanoparticles

Wang C, Levin AA, Fabbrici S, Nasi L, Karel J, Qian J, Barbosa CEV, Ouardi S, Albertini F, Schnelle W, Borrmann H, Fecher GH, Felser C (2016)

Publication Type: Journal article

Publication year: 2016

Journal

Journal of Materials Chemistry C Royal Society of Chemistry

Book Volume: 4

Pages Range: 7241-7252

Journal Issue: 30

DOI: 10.1039/c6tc01757f

Abstract

We report the structural and magnetic properties of chemically synthesized dual-phase Co2NiGa shape memory Heusler nanoparticles (NPs). Rietveld analysis of the X-ray diffraction (XRD) data reveals a dual-phase structure for all studied Co2NiGa NPs: the B2 ordered cubic austenite (β) and the tetragonal (γ or martensite β′) phases. We find that the fraction of the tetragonal γ-phase and magnetic properties of NPs consisting of β + γ phases prepared using a heating rate of 0.5 K min-1 can be tuned by varying the Ni-content. Higher saturation magnetization and Curie temperature are observed for Co2NiGa NPs with a higher fraction of the γ-phase. Dual-phase β + γ Co2NiGa NPs exhibit the highest Curie temperature (1153 K) of all known Heusler NPs. Furthermore, the martensite β′-phase is found to coexist with the β-phase for NPs synthesized using a higher heating rate of 2 K min-1. Co2NiGa NPs of mixed β + β′ phase are paramagnetic at room temperature and exhibit low magnetization due to the presence of the martensite phase. High temperature XRD measurements of Co2NiGa NPs with β + β′ phases confirm their irreversible phase transition of the β-phase starting at a temperature of 837 K and the structural stability of the tetragonal β′-phase. The developed new synthetic method makes it possible to fabricate Co2NiGa NPs with structure and properties tailored for high temperature magnetic shape memory devices at the nanoscale.

Involved external institutions

Max-Planck-Institut für Chemische Physik fester Stoffe (MPI CPfS) / Max Planck Institute for Chemical Physics of Solids DE Germany (DE) Consiglio Nazionale delle Ricerche (CNR) / National Research Council of Italy IT Italy (IT)

How to cite

APA:

Wang, C., Levin, A.A., Fabbrici, S., Nasi, L., Karel, J., Qian, J.,... Felser, C. (2016). Tunable structural and magnetic properties of chemically synthesized dual-phase Co2NiGa nanoparticles. Journal of Materials Chemistry C, 4(30), 7241-7252. https://doi.org/10.1039/c6tc01757f

MLA:

Wang, Changhai, et al. "Tunable structural and magnetic properties of chemically synthesized dual-phase Co2NiGa nanoparticles." Journal of Materials Chemistry C 4.30 (2016): 7241-7252.

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