Itinerant-electron metamagnetism and susceptibility maximum behavior in several kinds of Laves-phase compounds

Ohta, M.; Fukamichi, K.; Fujita, Akira; Saito, H.; Goto, T.

doi:10.1016/j.jallcom.2004.10.038

Cited by 6 publications

(4 citation statements)

References 34 publications

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“…On theoretical grounds, Wohlfarth and Rhodes showed that a maximum in the temperature dependence of magnetic susceptibility is expected due to the large positive curvature of the density of states and is characteristic of an IEM system [36]. Such a temperature dependence of susceptibility has indeed been observed in a number of compounds which exhibit IEM [37]. It was mentioned above that materials with negative M 4 coefficient in equation 12 exhibit IEM and FOT.…”

Section: Itinerant Electron Metamagnetism In Rco 2 Compoundsmentioning

confidence: 90%

Itinerant electron metamagnetism and magnetocaloric effect in RCo2-based Laves phase compounds

Singh

Суреш

Nigam

et al. 2007

Journal of Magnetism and Magnetic Materials

195

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Section: Itinerant Electron Metamagnetism In Rco 2 Compoundsmentioning

confidence: 90%

Itinerant electron metamagnetism and magnetocaloric effect in RCo2-based Laves phase compounds

Singh

Суреш

Nigam

et al. 2007

Journal of Magnetism and Magnetic Materials

195

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“…In particular, the ðTÞ maximum characterizes Co 3 Mo 3 C. A broad maximum observed for the itinerant electron system reminds us of a metamagnetic transition because the ðTÞ maximum is considered to correlate closely with IEMT and has been observed for almost all enhanced Pauli paramagnetic materials showing IEMT. [18][19][20] Hence, we measured high-field magnetization for Co 3 Mo 3 X. The results are shown in Fig.…”

Section: -2mentioning

confidence: 99%

“…His theory worked well in explaining experimental results especially of Co based Laves phase compounds and Co(S 1Àx Se x ) pyrites. [18][19][20]24,25) We apply this relation to Co 3 Mo 3 C. Using the hyperfine coupling constant and K orb , intrinsic ðT max Þ and ð0Þ are estimated to be 8:9 Â 10 À3 and 6:5 Â 10 À3 emu/(f.u.Ámol), respectively, by extrapolating high-temperature data. With these values, ac=b 2 is estimated as 0.66 for Co 3 Mo 3 C, which is outside the upper bound 9=20 ¼ 0:45 of the criterion proposed by Yamada, suggesting that Yamada's theory is too simple to explain the IEMT of Co 3 Mo 3 C. One of possible reasons for the discordance is that the magnetic order parameter M may not be uniform in this system owing to the presence of different magnetic sites.…”

Section: -2mentioning

confidence: 99%

Itinerant Electron Metamagnetism in η-Carbide-Type Compound Co₃Mo₃C

et al. 2010

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We report the magnetic properties of the cobalt molybdenum -carbide-type compounds Co 3 Mo 3 C and Co 3 Mo 3 N. The magnetic susceptibility of Co 3 Mo 3 C shows a Curie-Weiss temperature dependence at high temperatures and a broad maximum at around 100 K, whereas that of Co 3 Mo 3 N shows a nearly temperature-independent enhanced Pauli paramagnetic behavior. The absence of a magnetic long-range order was confirmed by the nuclear magnetic resonance technique in both the compounds. As expected from the broad maximum of , we observed an itinerant electron metamagnetic transition at around 37 T in Co 3 Mo 3 C.Ternary transition-metal interstitial compounds M 3 M 0 3 X (M: 3d transition metal, M 0 : 4d, 5d transition metal of early groups) are known to have the -carbide-type structure with the cubic space group Fd " 3 3m (227). Because of their hardness and catalytic ability, -carbide-type compounds have been studied for about half a century from a technological viewpoint. However, their electronic properties were less studied. In the structure, M, M 0 , and X atoms occupy the Wyckoff positions 16d/32e, 48f, and 16c, respectively. Focusing on M, which is expected to contribute mainly to the magnetic properties of the system, the 16d/32e sites form a three-dimensional (3D) network of the stella quadrangula (SQ) lattice. 1) SQ is a polyhedron as each face of a tetrahedron composed of 32e atoms is capped with another tetrahedron whose extra apex is a 16d atom. Because the SQ lattice is composed of tetrahedrons, magnetic properties are interesting from the aspect of geometrical frustration. Recently, we have reported a non-Fermi-liquid behavior in pure Fe 3 Mo 3 N without any tuning of pressure or concentration. 2) The magnetic properties of isostructural compounds are also expected to be of a wide variety.The synthetic routes of cobalt molybdenum -carbidetype compounds Co 3 Mo 3 X (X ¼ C, N) have been studied well. Co 3 Mo 3 N was first synthesized by Houmes et al. by ammonolysis of oxide precursors. 3) Following them, several methods of the reduction and nitridation of oxide precursors such as the plasma method 4) and urea method 5) have been reported. The resistivity shows a metallic behavior 5,6) and the magnetic susceptibility is of a Pauli paramagnet. 4,7) A superparamagnetic behavior and the absence of a magnetic long-range order were also suggested. 7) Although Co 3 Mo 3 C was first made by arc melting of elements, more moderate methods have been developed to avoid the excess occupation of Mo atoms of the 16d site. 8,9) Typical methods are reduction by H 2 and successive CO/CO 2 buffered gas treatment with cobalt tris(ethylenediamine) molybdate, 10)

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“…For example, crystalline YCo 2 has been investigated because of its itinerant-electron metamagnetism (IEM). 5,6 This field-driven first-order transition from the paramagnetic ground-state to a ferromagnetic state relates to a change in the band structure of 3d electrons by applying a magnetic field.…”

mentioning

confidence: 99%

Induced magnetic ordering in alloyed compounds based on Pauli paramagnet YCo2

Śniadecki

Werwiński

Szajek

et al. 2014

Journal of Applied Physics

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Intermetallic YCo2 compound is a Pauli exchange-enhanced paramagnet. Structural and magnetic properties melt-spun YCo2 pure and alloyed with Nb or Ti are presented. The samples crystallize in MgCu2-type phase with lattice constant a changing from 7.223 Å for YCo2, through 7.213 Å for Y0.9Nb0.1Co2 to 7.192 Å for Y0.9Ti0.1Co2, where Y atoms are replaced by Nb or Ti atoms. Nanocrystalline phases can be produced by appropriate cooling rates for the solidification process. By the synthesis process free volumes, vacancies, and alloyed atoms are introduced into the YCo2 intermetallic. Ab-initio calculations have been performed to investigate the effects of substitution on the spin-split electronic band structure in the ordered YCo2. A ferrimagnetic ground state is found in the alloyed systems with substitution on the Y-site which is energetically favorable compared to point defects on Co-sites. However, the experimentally found increased magnetic ordering in alloyed YCo2 appears to be based on microstructure effects.

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Itinerant-electron metamagnetism and susceptibility maximum behavior in several kinds of Laves-phase compounds

Cited by 6 publications

References 34 publications

Itinerant electron metamagnetism and magnetocaloric effect in RCo2-based Laves phase compounds

Itinerant electron metamagnetism and magnetocaloric effect in RCo2-based Laves phase compounds

Itinerant Electron Metamagnetism in η-Carbide-Type Compound Co₃Mo₃C

Induced magnetic ordering in alloyed compounds based on Pauli paramagnet YCo2

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Itinerant-electron metamagnetism and susceptibility maximum behavior in several kinds of Laves-phase compounds

Cited by 6 publications

References 34 publications

Itinerant electron metamagnetism and magnetocaloric effect in RCo2-based Laves phase compounds

Itinerant electron metamagnetism and magnetocaloric effect in RCo2-based Laves phase compounds

Itinerant Electron Metamagnetism in η-Carbide-Type Compound Co3Mo3C

Induced magnetic ordering in alloyed compounds based on Pauli paramagnet YCo2

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Itinerant Electron Metamagnetism in η-Carbide-Type Compound Co₃Mo₃C