Phase Equilibria and Magnetic Phases in the Ce-Fe-Co-B System

A powder neutron scattering study of atom substitution in Nd 2 (Fe 1− Co ) 14 B, Y 2 (Fe 1− Co ) 14 B and Ce 2 (Fe 1− Co ) 14 B compounds is presented. Compared to previous studies, this one benefits from the considerable progress made in neutron diffraction measurements and their analysis during the last 15 years. The normalization of the occupancy values to those expected from a random distribution permits to reveal small deviations from random distribution. On all crystallographic sites some preferential occupancy is evidenced, the extent of which depends on the Co versus Fe content. A statistical model quantitatively describing site occupancies is proposed, which allows us to study the extreme cases of very dilute substitutions. Steric considerations primarily determine atom substitution, more particularly Fe-substitution in Co-rich compounds. The enthalpy of mixing must also be considered to describe Co preferential occupancies more exactly.

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“…∑ 56 = 1 (13) and ∑ 56 1 − = 1 (14) with 56 being the total number of TM sites per unit cell. From ( 11) and ( 13), one derives:…”

Section: Discussionmentioning

confidence: 99%

“…In Ce compounds, only two samples presented the desired structure, those with = 0 and 0.286. According to literature the upper solubility limit for Co in Ce 2 (Fe 1− Co ) 14 B is less than = 0.4 [12,13].…”

Section: Experimental Protocol and Preferential Occupancy Determinationmentioning

confidence: 98%

Preferential Co and Fe atom occupancy in R2(Fe1-xCo )14B intermetallic compounds (R = Nd, Y and Ce)

Eslava

Ito

Colin

et al. 2021

Journal of Alloys and Compounds

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“…It was reported that magnetic Ce 2 Fe 14-x Co x B (0≤x≤4.76) is formed in the Ce-Fe-Co-B system [6]. To introduce a practical hard magnet, the most important step is the determination of its intrinsic magnetic properties.…”

Section: A C C E P T E Dmentioning

confidence: 99%

“…The saturation magnetization was obtained in external field up to 50 kOe. Since Ce-Fe-Co-B is a complex multi-component system, it is extremely difficult to obtain single phase sample, especially because certain magnetic phases such as Ce 2 (Fe, Co) 14 B form through a peritectic reaction [6]. Practically, in order for the magnetic properties of the alloys to be attributed to the magnetic phase, samples should contain at least seventy mass percent of the magnetic phase of interest with certain amounts of secondary phases which could help impeding domain wall motion [3].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Intrinsic magnetic properties of Ce2(Fe, Co)14B and its modifications by Ni and Cu

Wang

Medraj

2018

Journal of Alloys and Compounds

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The intrinsic magnetic properties of Ce 2 Fe 14-x Co x B (x≤4.76) are studied at 25°C using key alloys annealed at 900°C for 25 days. The saturation magnetization (M s ) and the Curie temperature (T c ) of Ce 2 Fe 14-x Co x B increase with Co content. However, the anisotropy field (H a ) of Ce 2 Fe 14-x Co x B diminishes precipitously with Co content. The process of crystal structure refinement indicates that the saturation magnetization of Ce 2 Fe 14-x Co x B is related to the site occupancy of Co atoms at different Fe atomic sites.Co atoms prefer to occupy 8j2 site, followed by 16k2, 4e and 16k1 sites sequentially.Moreover, Co atoms occupying 8j2 site are more effective leading to an increase in theThe individual effects of Ni or Cu on the intrinsic magnetic properties of Ce 2 Fe 12.98x Co 1.02 Ni x B and Ce 2 Fe 12.98-y Co 1.02 Cu y B are evaluated. The maximum solid solubilities of Ni and Cu in Ce 2 Fe 12.98 Co 1.02 B at 900ºC are found to be 8 at.% and 0.8 at.%, respectively. Ni or Cu enhances T c , but decreases both M s and H a of Ce 2 Fe 12.98 Co 1.02 B. The paper also discussed the combined effects of Ni and Cu on the intrinsic magnetic properties of Ce 2 Fe 12.98 Co 1.02 B. The M s of Ce 2 Fe 12.98-x-y Co 1.02 Ni x Cu y B (0≤x≤0.41, y≈0.119) increases after doping with both Ni and Cu, reaching around 155 emu/g. Meanwhile, the H a and the T c are measured to be near 24 kOe and 280°C, respectively.

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“…The intrinsic magnetic properties of Ce 2 Fe 14-x Co x B have been reported in [4]. So far, there is a lack of magnetic domain structure investigations of Ce 2 Fe 14-x Co x B.…”

Section: Introductionmentioning

confidence: 99%

Magnetic force microscopic study of Ce2(Fe, Co)14B, and its modifications by Ni and Cu

Wang

Medraj

2018

Journal of Magnetism and Magnetic Materials

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The domain width and domain wall energy of the Ce 2 Fe 14-x Co x B solid solution are studied for the first time in this work. The influence of Co content on these properties has been analyzed with the aid of magnetic force microscopy using diffusion couple and key alloys. The domain widths of Ce 2 Fe 14-x Co x B decreased with increasing Co content at about 0.02 μm per 1 at.% Co. In Ce 2 Fe 14-x Co x B, phase shift, domain width and saturation magnetization are related in a way that lower average domain width is associated with higher phase shift and higher saturation magnetization. The highest domain wall energy of Ce 2 Fe 14-x Co x B is measured as 31.7 erg/cm 2 after dissolving 14 at.% Co (x=2.38). The effects of Ni and Cu on the domain width and domain wall energy of Ce 2 Fe 14-x Co x B (x=1.02) are also studied and reported using response surfaces. The domain width and domain wall energy of this solid solution increased after doping with 1 at.% Ni at constant Co content of 6 at.%, measuring 1.39 μm for domain width and 33.4 erg/cm 2 for domain wall energy. Both properties were determined as 0.71 μm and 18.6 erg/cm 2 , respectively, after doping with 0.8 at.% Cu, while keeping Co content constant at 6 at.%. When Ce 2 Fe 14-x Co x B (x=1.02) is doped with both Ni (1 at.%) and Cu (0.8 at.%), the domain width and domain wall energy measured 0.99 μm and 33.8 erg/cm 2 , respectively.

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Phase Equilibria and Magnetic Phases in the Ce-Fe-Co-B System

Cited by 12 publications

References 18 publications

Preferential Co and Fe atom occupancy in R2(Fe1-xCo )14B intermetallic compounds (R = Nd, Y and Ce)

Preferential Co and Fe atom occupancy in R2(Fe1-xCo )14B intermetallic compounds (R = Nd, Y and Ce)

Intrinsic magnetic properties of Ce2(Fe, Co)14B and its modifications by Ni and Cu

Magnetic force microscopic study of Ce2(Fe, Co)14B, and its modifications by Ni and Cu

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