Local atomic order in the vicinity of Cu2 dumbbells in TbCu7-type YCu6.576 studied by Bragg and total scattering techniques

Černý, Radovan; Filinchuk, Yaroslav; Brühne, Stefan

doi:10.1016/j.intermet.2009.03.010

Cited by 17 publications

(5 citation statements)

References 28 publications

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“…The local correlation between missing atom in 1a position and shrunk 6l hexagon has been proved in Ref. [20] in the case of Yb-Cu system using the Pair Distribution Function. This model is valid only for a limited fraction of dumbbells.…”

Section: Intermetallic Compoundsmentioning

confidence: 96%

LaNi5 related AB5 compounds: Structure, properties and applications

Joubert

Paul‐Boncour

Cuevas

et al. 2021

Journal of Alloys and Compounds

103

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This paper is a comprehensive review of the properties of LaNi 5 derivatives and other AB 5 compounds with CaCu 5 crystal structure (A=Y, lanthanide, Th and B=transition metal, Al, Ge, Si, Sn) and their applications. The crystal structures of the intermetallic compounds are described considering their chemical composition and off-stoichiometry. Same approach is conducted for the metallic hydrides formed by direct reaction of dihydrogen with the intermetallic. The thermodynamic properties of the sorption reaction are presented regarding equilibrium pressure and reversibility. In a second step, outstanding applications are given focusing first on magnetic properties and electrochemical energy storage. Finally, other uses such as gas storage, heat exchange, compression or gas separation and purification are highlighted showing the tremendous possibilities offered by this class of materials.

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Section: Intermetallic Compoundsmentioning

confidence: 96%

LaNi5 related AB5 compounds: Structure, properties and applications

Joubert

Paul‐Boncour

Cuevas

et al. 2021

Journal of Alloys and Compounds

103

View full text Add to dashboard Cite

show abstract

“…However the slight Ce depletion and the presence of Ta suggest the possibility of minor deviations from the classic CaCu 5type crystal structure towards various channel disorders or "dumb-bell" problems characterized elsewhere. [48][49][50] These deviations were accounted for in our structural models and refinements [Figs. 4,5].…”

Section: A Sem/eds Examinations and Compositionmentioning

confidence: 99%

Single-Crystal Permanent Magnets: Extraordinary Magnetic Behavior in theTa-,Cu-, andFe-Substituted
Lamichhane
¹
,
Onyszczak
²
,
Palasyuk
³

et al. 2019
Phys. Rev. Applied

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To reduce material and processing costs of commercial permanent magnets and to attempt to fill the empty niche of energy products, 10-20 MGOe, between low-flux (ferrites, alnico) and highflux (Nd2Fe14B-and SmCo5-type) magnets, we report synthesis, structure, magnetic properties and modeling of Ta, Cu and Fe substituted CeCo5. Using a self-flux technique, we grew single crystals of I-Ce15.1Ta1.0Co74.4Cu9.5, II-Ce16.3Ta0.6Co68.9Cu14.2, III-Ce15.7Ta0.6Co67.8Cu15.9, IV-Ce16.3Ta0.3Co61.7Cu21.7 and V-Ce14.3Ta1.0Co62.0Fe12.3Cu10.4. X-ray diffraction analysis (XRD) showed that these materials retain a CaCu5 substructure and incorporate small amounts of Ta in the form of "dumb-bells", filling the 2e crystallographic sites within the 1D hexagonal channel with the 1a Ce site, whereas Co, Cu and Fe are statistically distributed among the 2c and 3g crystallographic sites. Scanning electron microscopy, energy dispersive X-ray spectroscopy (SEM-EDS) and scanning transmission electron microscopy (STEM) examinations provided strong evidence of the single-phase nature of the as-grown crystals, even though they readily exhibited significant magnetic coercivities of ∼1.6-∼1.8 kOe caused by Co-enriched, nano-sized, structural defects and faults that can serve as pinning sites. Heat treatments at 1040 • C for 10 h and a hardening at 400 • C for 4 h lead to the formation of a so-called "composite crystal" with a bimodal microstructure that consists of a Tapoor matrix and Ta-rich laminal precipitates. Formation of the "composite crystal" during the heat treatment creates a 3D array of extended defects within a primarily single grain single crystal, which greatly improves its magnetic characteristics. Possible causes of the formation of the "composite crystal" may be associated with Ta atoms leaving matrix interstices at lower temperatures and/or matrix degradation induced by decreased miscibility at lower temperatures. Fe strongly improves both the Curie temperature and magnetization of the system resulting in (BH)max.≈13 MGOe at room temperature.

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“…However the slight Ce depletion and the presence of Ta suggest the possibility of minor deviations from the classic CaCu 5 -type crystal structure towards various channel disorders or "dumb-bell" problems characterized elsewhere. [47][48][49] These deviations were accounted for in our structural models and refinements [Figs. 4,5].…”

Section: A Sem/eds Examinations and Compositionmentioning

confidence: 99%

Single Crystal Permanent Magnet: Extraordinary Magnetic Behavior in the ta, Cu and Fe Substituted CeCo5 System

Lamichhane,

Onyszczak,

Palasyuk

et al. 2018

Preprint

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To reduce material and processing costs of commercial permanent magnets and to attempt to fill the empty niche of energy products, 10 -20 MGOe, between low-flux (ferrites, alnico) and highflux (Nd2Fe14B-and SmCo5-type) magnets, we report synthesis, structure, magnetic properties and modeling of Ta, Cu and Fe substituted CeCo5. Using a self-flux technique, we grew single crystals of I -Ce15.1Ta1.0Co74.4Cu9.5, II -Ce16.3Ta0.6Co68.9Cu14.2, III -Ce15.7Ta0.6Co67.8Cu15.9, IV -Ce16.3Ta0.3Co61.7Cu21.7 and V -Ce14.3Ta1.0Co62.0Fe12.3Cu10.4. X-ray diffraction analysis (XRD) showed that these materials retain a CaCu5 substructure and incorporate small amounts of Ta in the form of "dumb-bells", filling the 2e crystallographic sites within the 1D hexagonal channel with the 1a Ce site, whereas Co, Cu and Fe are statistically distributed among the 2c and 3g crystallographic sites. Scanning electron microscopy, energy dispersive X-ray spectroscopy (SEM-EDS) and scanning transmission electron microscopy (STEM) examinations provided strong evidence of the single-phase nature of the as-grown crystals, even though they readily exhibited significant magnetic coercivities of ∼1.6 -∼1.8 kOe caused by Co-enriched, nano-sized, structural defects and faults that can serve as pinning sites. Heat treatments at 1040 • C for 10 h and a hardening at 400 • C for 4 h lead to the formation of a so-called "composite crystal" with a bimodal microstructure that consists of a Tapoor matrix and Ta-rich laminal precipitates. Formation of the "composite crystal" during the heat treatment creates a 3D array of extended defects within a primarily single grain single crystal, which greatly improves its magnetic characteristics. Possible causes of the formation of the "composite crystal" may be associated with Ta atoms leaving matrix interstices at lower temperatures and/or matrix degradation induced by decreased miscibility at lower temperatures. Fe strongly improves both the Curie temperature and magnetization of the system resulting in (BH)max.≈13 MGOe at room temperature.

show abstract

Local atomic order in the vicinity of Cu2 dumbbells in TbCu7-type YCu6.576 studied by Bragg and total scattering techniques

Cited by 17 publications

References 28 publications

LaNi5 related AB5 compounds: Structure, properties and applications

LaNi5 related AB5 compounds: Structure, properties and applications

Single-Crystal Permanent Magnets: Extraordinary Magnetic Behavior in theTa-,Cu-, andFe-Substituted
Lamichhane
¹
,
Onyszczak
²
,
Palasyuk
³

et al. 2019
Phys. Rev. Applied

Single Crystal Permanent Magnet: Extraordinary Magnetic Behavior in the ta, Cu and Fe Substituted CeCo5 System

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Local atomic order in the vicinity of Cu2 dumbbells in TbCu7-type YCu6.576 studied by Bragg and total scattering techniques

Cited by 17 publications

References 28 publications

LaNi5 related AB5 compounds: Structure, properties and applications

LaNi5 related AB5 compounds: Structure, properties and applications

Single-Crystal Permanent Magnets: Extraordinary Magnetic Behavior in theTa-,Cu-, andFe-SubstitutedLamichhane1, Onyszczak2, Palasyuk3 et al. 2019Phys. Rev. Applied

Single Crystal Permanent Magnet: Extraordinary Magnetic Behavior in the ta, Cu and Fe Substituted CeCo5 System

Contact Info

Product

Resources

About

Single-Crystal Permanent Magnets: Extraordinary Magnetic Behavior in theTa-,Cu-, andFe-Substituted
Lamichhane
¹
,
Onyszczak
²
,
Palasyuk
³

et al. 2019
Phys. Rev. Applied