Permanent magnetic materials are essential for technological applications, with the majority of available magnets being either ferrites or materials composed of critical rare-earth elements, such as well-known Nd
2Fe
14B. The binary Fe
2P material emerges as a promising candidate
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Permanent magnetic materials are essential for technological applications, with the majority of available magnets being either ferrites or materials composed of critical rare-earth elements, such as well-known Nd
2Fe
14B. The binary Fe
2P material emerges as a promising candidate to address the performance gap, despite its relatively low Curie temperature
of 214 K. In this study, density functional theory was employed to investigate the effect of Si and Co substitution on the magnetic moments, magnetocrystalline anisotropy energy (MAE) and Curie temperature in
Co
yP
1−xSi
x compounds. Our findings indicate that Si substitution enhances magnetic moments due to the increase in 3
f-3
f and 3
f-3
g interaction energies, which also contribute to higher
values. Conversely, Co substitution leads to a reduction in magnetic moments, attributable to the inherently lower magnetic moments of Co. In all examined cases of different Si concentrations, such as hexagonally structured
Co
yP,
Co
yP
0.92Si
0.08 and
Co
yP
0.84Si
0.16, Co substitution increases the Curie temperatures by augmenting 3
g-3
g exchange interaction energies. Both Si and Co substitutions decrease the magnetocrystalline anisotropy energy, resulting in the loss of the easy magnetization direction at higher Co contents. However, higher Si concentrations appear to confer resilience against the loss. In summary, Si and Co substitutions effectively modify the investigated magnetic properties. Nonetheless, to preserve a high MAE, the extent of substitution should be optimized.
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