X-ray measurement of order in CuAu

Roberts, B. W.

doi:10.1016/0001-6160(54)90194-7

Cited by 182 publications

(50 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In order to evaluate the long-range ordering degree of the fct phase for the as-synthesized NPs in more detail, the order parameter S is employed. An approximate relation between S and c/a can be written as follows: 33 where is (c/a)Sf the axial ratio for the fully ordered phase, c/a ratio is for the partially ordered phase. S = 1 in this equation corresponds to the fully ordered phase.…”

Section: Resultsmentioning

confidence: 99%

Direct chemical synthesis of L1₀-FePtAu nanoparticles with high coercivity

Mukherjee

Tian

et al. 2014

Nanoscale

View full text Add to dashboard Cite

We report a facile synthesis of hard magnetic L10-FePtAu nanoparticles by coreduction of Fe(acac)3, Pt(acac)2 (acac = acetylacetonate), and gold acetate in oleylamine. In the current reaction condition, NP sizes are controlled to be 5.5 to 11.0 nm by changing the amount of Au doping. When the Au composition in the NPs is higher than 14%, the hard magnetic NPs are directly obtained without any annealing. The highest coercivity of 12.15 kOe at room temperature could be achieved for the NPs with 32% Au doping, which is much higher than the coercivities reported by the previous studies on solution-synthesized FePt nanoparticles. The reported one-pot synthesis of L10-FePtAu NPs may help to build superstrong magnets for magnetic or data-storage applications.

show abstract

Section: Resultsmentioning

confidence: 99%

Direct chemical synthesis of L1₀-FePtAu nanoparticles with high coercivity

Mukherjee

Tian

et al. 2014

Nanoscale

View full text Add to dashboard Cite

show abstract

“…A better analogy might be found in the intragroup compounds CuAu and NiPt that display ordering transitions at moderate temperatures (681 K and 898 K, respectively). 57,58 CuAu would have an ionicity of r σ = 0.21 in the St. John-Bloch plot, but it has such low covalency (r −1 π = 0.43) that it does not appear in the same frame as IV-VI compounds. Meanwhile the strongly covalent intragroup IV-IV compound SiC (r −1 π = 3.1) forms a refractory, tetrahedrallycoordinated diamond lattice.…”

Section: B Crystal Chemistry and High-temperature Transformationmentioning

confidence: 99%

Chemical ordering rather than random alloying in SbAs

Shoemaker

Chasapis

et al. 2013

Phys. Rev. B

View full text Add to dashboard Cite

The semimetallic Group V elements display a wealth of correlated electron phenomena due to a small indirect band overlap that leads to relatively small, but equal, numbers of holes and electrons at the Fermi energy with high mobility. Their electronic bonding characteristics produce a unique crystal structure, the rhombohedral A7 structure, which accommodates lone pairs on each site. Here we show via single-crystal and synchrotron x-ray diffraction that SbAs is a compound and the A7 structure can display chemical ordering of Sb and As, which were previously thought to mix randomly. Formation of this compound arises due to differences in electronegativity that are common to IV-VI compounds of average group V such as GeTe, SnS, PbS, and PbTe, and also ordered intra-period compounds such as CuAu and NiPt. High-temperature diffraction studies reveal an order-disorder transition around 550 K in SbAs, which is in stark contrast to IV-VI compounds GeTe and SnTe that become cubic at elevated temperatures but do not disorder. Transport and infrared reflectivity measurements, along with first-principles calculations, confirm that SbAs is a semimetal, albeit with a direct band separation larger than that of Sb or As. Because even subtle substitutions in the semimetals, notably Bi1−xSbx, can open semiconducting energy gaps, a further investigation of the interplay between chemical ordering and electronic structure on the A7 lattice is warranted.

show abstract

“…Nous remarquerons que la courbe relative ~t AuCu est tr~s diff6rente de celle que propose Roberts (1954). En effet cet auteur attribue encore ~t S la valeur 0,97 au voisinage de la temp6rature de transition I -+ II alors que nous avons mesur6 S=0,80 ~t 376°C.…”

Section: Techniques Exp6rlmentalesunclassified

“…L'enthalpie de formation de cet alliage est de -2145 cal/atome g h 160°C (S= 1), elle n'est plus que -1950 cal/atome g g 375,5°C et environ 1320 cal/atome g en phase c~ ~t 419°C (Hertz, 1967a). L'6nergie raise en jeu au cours de la mise en d6sordre est donc de l'ordre de 800 cal/atome g dont 200 correspondent h la mise en d6sordre partiel de la phase I. I1 apparait que la variation corr61ative de 20% du degr6 d'ordre que nous proposons rend mieux compte de la variation de l'enthalpie que celle de Roberts (1954) qui n'est que 3%. Nous pensons qu'une trempe trop lente de ces alliages a conduit cet auteur/: ces valeurs trop 61ev6es.…”

Section: Techniques Exp6rlmentalesunclassified

Etude radiocristallographique des transformations d'ordre de type α_désordre<->I_ordredans les alliages ternaires or cuivre nickel et l'alliage binaire de composition remarquable AuCu₃

Gantois¹

1968

J Appl Cryst

View full text Add to dashboard Cite

The study of the scattering outside the Bragg reflexions shows no local order in the ordered phase I of alloys such as Au (50 at. %) Cu (46 at. %) Ni (4 at. %) even for the smallest degree of long range order. The modulation of the scattering appears only with the presence of short range order in the disordered α phase. There is evidence of a two‐phase region on the equilibrium diagram at the AuCu3 stoichiometric composition.

show abstract

X-ray measurement of order in CuAu

Cited by 182 publications

References 10 publications

Direct chemical synthesis of L1₀-FePtAu nanoparticles with high coercivity

Direct chemical synthesis of L1₀-FePtAu nanoparticles with high coercivity

Chemical ordering rather than random alloying in SbAs

Etude radiocristallographique des transformations d'ordre de type α_désordre<->I_ordredans les alliages ternaires or cuivre nickel et l'alliage binaire de composition remarquable AuCu₃

Contact Info

Product

Resources

About

X-ray measurement of order in CuAu

Cited by 182 publications

References 10 publications

Direct chemical synthesis of L10-FePtAu nanoparticles with high coercivity

Direct chemical synthesis of L10-FePtAu nanoparticles with high coercivity

Chemical ordering rather than random alloying in SbAs

Etude radiocristallographique des transformations d'ordre de type αdésordre<->Iordredans les alliages ternaires or cuivre nickel et l'alliage binaire de composition remarquable AuCu3

Contact Info

Product

Resources

About

Direct chemical synthesis of L1₀-FePtAu nanoparticles with high coercivity

Direct chemical synthesis of L1₀-FePtAu nanoparticles with high coercivity

Etude radiocristallographique des transformations d'ordre de type α_désordre<->I_ordredans les alliages ternaires or cuivre nickel et l'alliage binaire de composition remarquable AuCu₃