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| Main Authors: | , , , |
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| Format: | Preprint |
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2021
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| Online Access: | https://arxiv.org/abs/2105.13523 |
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| _version_ | 1866910492302245888 |
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| author | Seema Kumar, Dileep Deshpande, U. P. Gupta, Mukul |
| author_facet | Seema Kumar, Dileep Deshpande, U. P. Gupta, Mukul |
| contents | This work demonstrates synthesis and study of fcc-Co derived from an isostructural Co4N. Diffusion measurements carried out in this work, reveal that N self-diffusion is the swiftest in Co4N compared to other transition metal nitrides or even the mononitride CoN. By the application of a high substrate temperature (Ts) growth or thermal annealing temperature (Ta); N diffuses out from the fcc-Co4N above 573 K leaving behind a high purity fcc-Co phase. Generally, Co grows in a hcp structure and a (partial) hcp to fcc-Co transformation takes place around 700 K or above 70 GPa. The proposed route through nitridation and diffusion of N not only bring down the phase transition temperature, an impurity present in the form of hcp-Co can be avoided altogether. Oriented Co4N(111) thin films were grown using a CrN(111) template on a quartz substrate using a dc magnetron sputtering. Samples were grown at different Ts or room temperature grown Co4N samples were annealed at different Ta. Analysis using x-ray diffraction, N K-edge x-ray absorption, x-ray photoelectron and secondary ion mass spectroscopy confirmed the formation of fcc-Co4N or fcc-Co phases. It was found that Co-N bonding and N concentration get significantly reduced at a high Ts or Ta. Magnetization measurements combining ex-situ and in-situ magneto-optical Kerr effect showed differences in anisotropy and coercivity of Co4N and fcc-Co samples. Combining structural, electronic and magnetization measurements, it has been observed that a high purity fcc-Co can be conveniently derived from the isostructural Co4N aided by an exceptionally high N self-diffusion in Co4N. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2105_13523 |
| institution | arXiv |
| publishDate | 2021 |
| record_format | arxiv |
| spellingShingle | Synthesis and study of fcc-Co derived from isostructural Co4N Seema Kumar, Dileep Deshpande, U. P. Gupta, Mukul Materials Science This work demonstrates synthesis and study of fcc-Co derived from an isostructural Co4N. Diffusion measurements carried out in this work, reveal that N self-diffusion is the swiftest in Co4N compared to other transition metal nitrides or even the mononitride CoN. By the application of a high substrate temperature (Ts) growth or thermal annealing temperature (Ta); N diffuses out from the fcc-Co4N above 573 K leaving behind a high purity fcc-Co phase. Generally, Co grows in a hcp structure and a (partial) hcp to fcc-Co transformation takes place around 700 K or above 70 GPa. The proposed route through nitridation and diffusion of N not only bring down the phase transition temperature, an impurity present in the form of hcp-Co can be avoided altogether. Oriented Co4N(111) thin films were grown using a CrN(111) template on a quartz substrate using a dc magnetron sputtering. Samples were grown at different Ts or room temperature grown Co4N samples were annealed at different Ta. Analysis using x-ray diffraction, N K-edge x-ray absorption, x-ray photoelectron and secondary ion mass spectroscopy confirmed the formation of fcc-Co4N or fcc-Co phases. It was found that Co-N bonding and N concentration get significantly reduced at a high Ts or Ta. Magnetization measurements combining ex-situ and in-situ magneto-optical Kerr effect showed differences in anisotropy and coercivity of Co4N and fcc-Co samples. Combining structural, electronic and magnetization measurements, it has been observed that a high purity fcc-Co can be conveniently derived from the isostructural Co4N aided by an exceptionally high N self-diffusion in Co4N. |
| title | Synthesis and study of fcc-Co derived from isostructural Co4N |
| topic | Materials Science |
| url | https://arxiv.org/abs/2105.13523 |