Effects of the C interstitial doping on the magnetic properties of LTP MnBi

• Published in: Journal of magnetism and magnetic materials Vol. 532; p. 167997
• Main Authors: Hirian, R., Dudric, R., Isnard, O., Kuepper, K., Coldea, M., Barbu-Tudoran, L., Pop, V., Benea, D.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.08.2021; Elsevier BV; Elsevier
• Subjects: Ab-initio calculations; Anisotropy; Core-levels X-ray photoemission; Crystal structure; Diffraction patterns; Low temperature; Magnetic measurement; Magnetic moments; Magnetic properties; Magnetism; Magnetization measurements; Magneto-crystalline anisotropy; Permanent magnets; Photoelectric emission; Physics; Magnetization measurements; Permanent magnets; Core-levels X-ray photoemission; Ab-initio calculations; Magneto-crystalline anisotropy
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2021.167997

•MnBi and MnBiC samples were obtained by arc melting followed by annealing at 400 °C.•Large LTP phase content (>72%) obtained by Rietveld refinements.•Charge flow from Mn and Bi atoms to C atoms provides the formation of MnBiC LTP phase.•Based on the magnetization measurements at 300 K, increased MAE by C doping was found.•Magnetization increases by C addition by both theoretical and experimental investigations. Experimental and theoretical investigations on the structural and magnetic properties of the MnBi and MnBiC hard magnetic phases are presented. X-ray diffraction patterns showed that the highest concentration of MnBi low-temperature phase (LTP) was obtained for annealing at 400 °C for 12 h. X-ray photoemission measurements (XPS) of the core levels (Mn 2p and 3d; Bi 4d and 5p, respectively) show chemical shifts by C addition, providing evidence that the C atoms enter the MnBi structure in the vicinity of both type of metallic atoms. C atoms were assumed to occupy the 2d interstitial crystal sites of the hexagonal NiAs structure type, as suggested in earlier studies. The theoretical calculations show that C addition enhances slightly the magnetic moment of the samples compared to pristine LTP MnBi, in agreement with our magnetic measurements. Also, following both theoretical and experimental investigations, we obtained increased magnetocrystalline anisotropy energy (MAE) by adding C as interstitial dopant.