Temperature- and composition-driven changes in site occupation of indium solutes in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Gd</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>+</mml:mo><mml:mn>3</mml:mn><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Al</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mi>−</mml:mi><mml:mn>3</mml:mn><mml:mi>x</mm

Zacate, Matthew O.; Collins, Gary S.

doi:10.1103/physrevb.69.174202

Cited by 19 publications

(8 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Temperature and composition driven changes of the site occupation of 111 In in R-Al and Ni-Al phases and two-phase mixtures of Pd-Ga and Fe-Al intermetallic compounds have recently been reported by Collins and co-workers. [9][10][11] Similar studies for 111 In and…”

Section: Introductionmentioning

confidence: 59%

Electric field gradients in the rare earth–aluminium compoundsRAl2andRAl3studied by
Forker
¹
,
Presa
²

2007
Phys. Rev. B

View full text Add to dashboard Cite

Perturbed angular correlation ͑PAC͒ spectroscopy has been used to investigate the electric field gradient ͑EFG͒ at the probe nucleus 111 In/ 111Cd in the paramagnetic phase of the rare earth ͑R͒-aluminium compounds RAl 2 for all R elements and Y and in RAl 3 for R = Gd, Tm, Yb, Lu. The nuclear electric quadrupole interaction ͑QI͒ between the EFG and the 111 Cd quadrupole moment was measured as a function of temperature in the range T C Ͻ T ഛ 1200 K. In the second half of the RAl 2 series and in the RAl 3 compounds, except for YbAl 3 , the quadrupole frequency q shows the monotonous decrease with increasing temperature normally observed with closed-shell probe nuclei in metallic systems. In the early members of the RAl 2 series, however, q ͑T͒ passes through a maximum at T ϳ 300 K. It is proposed that this unusual behavior reflects a contribution of the 4f shell of the R constituents to the EFG at the Al site which is quenched at higher temperatures by thermal averaging of the 4f quadrupole moment. In the intermediate-valence compound YbAl 3 the temperature dependence of the QI exhibits a shallow maximum which can be related to the temperature variation of the 4f hole occupation. Furthermore the PAC spectra provide information on the site preference of the Cd. The temperature dependence of the relaxation rates shows an Arrhenius behavior with jump activation enthalpies E A = 1.6͑1͒ eV for R = Tm, Lu and E A = 1.2͑1͒ eV for R =Yb.

show abstract

Section: Introductionmentioning

confidence: 59%

Electric field gradients in the rare earth–aluminium compoundsRAl2andRAl3studied by
Forker
¹
,
Presa
²

2007
Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…The most useful experimental measure of site preference is the ratio of fractions of probes on the two sites, and, inserting a factor 2 for the 2:1 ratio of sites on the Al and Gd-sublattices, 2 f Gd f Al = In Gd In Al = Al Gd exp −G tr k B T . Since the site-fraction ratio depends on sample composition through the antisite mole fraction [Al Gd ], it is not possible to immediately determine the difference of site-enthalpies of In Gd and In Al from an overall fitted activation enthalpy without making additional assumptions or approximations [1].…”

mentioning

confidence: 99%

Site preferences of indium impurity atoms in intermetallics having Al3Ti or Al3Zr crystal structures

2007

Self Cite

View full text Add to dashboard Cite

Site-fractions of indium impurity probe atoms occupying up to three inequivalent Al-sites in Al 3 Ti, Al 3 V and Al 3 Zr phases were measured using perturbed angular correlation of gamma rays (PAC). Sites were identified via characteristic nuclear quadrupole interactions. Ratios of site-fractions were measured in thermal equilibrium in the range 600 to 1,210 K. Arrhenius plots of the ratios were fitted with thermally activated expressions, yielding differences in vibrational entropies and siteenthalpies. Enthalpy differences were greatest for Al 3 Zr, ∼0.22 eV, and smaller for Al 3 Ti and Al 3 V, which is correlated with the excess volume of the transition-metal atom over the Al-atom. Vibrational entropy differences were small, in the range 0 to −0.25 k B .The site preference of dilute 111 In impurities in the Laves phase GdAl 2 was previously studied as a function of composition and temperature [1]. Occupied Gdand Al-sites were determined through measurements of quadrupole interactions using the method of perturbed angular correlation of gamma rays (PAC). In that study, 111 In impurity probe atoms were observed to switch between sites of different elements. The ratio of site fractions of indium solutes on Gd-and Al-sites was found to be thermally activated, with solutes transferring from the Gd-to Alsublattice with increasing temperature. Transfer takes place heuristically through the reaction In Gd + Al Al ⇔ In Al + Al Gd , in which Al Gd is an antisite atom that is either created or destroyed. Applying the law of mass action to the reaction leads to [In Al ][Al Gd ])/[In Gd ] = exp(−G tr /k B T), in which G tr is the free energy of transfer

show abstract

“…For example, the site occupation of indium in GdAl 2 was determined this way. The two primary EFGs observed had ω Q = 0 and ω Q = 7.5 Mrad/s with η = 0, which correspond to probes occupying the Gd site (with 43m site symmetry) and the Al site (with 3m site symmetry) respectively [60]. As a second example, site occupation of indium in Zr 2 Rh was based on observed EFG symmetries.…”

Section: Examplesmentioning

confidence: 92%

Perturbed Angular Correlation Spectroscopy – A Tool for the Study of Defects and Diffusion at the Atomic Scale

Zacate

Jaeger

2011

DDF

Self Cite

View full text Add to dashboard Cite

Abstract. This paper provides an introduction to perturbed angular correlation (PAC) spectroscopy in the context of its application in the study of point defects and diffusion. It emphasizes what we anticipate to be of interest to non-PAC specialists who are interested in understanding variations in how PAC results are presented by different research groups and in how physical quantities such as defect formation energies, association energies, and migration barriers can be extracted from analysis of PAC spectra. Numerous citations are included to emphasize the universality of the analysis methods across different classes of materials including metallic, ceramic, and semiconducting compounds.

show abstract

Temperature- and composition-driven changes in site occupation of indium solutes inGd1+3xAl2−3x

Cited by 19 publications

References 22 publications

Electric field gradients in the rare earth–aluminium compoundsRAl2andRAl3studied by
Forker
¹
,
Presa
²

2007
Phys. Rev. B

Electric field gradients in the rare earth–aluminium compoundsRAl2andRAl3studied by
Forker
¹
,
Presa
²

2007
Phys. Rev. B

Site preferences of indium impurity atoms in intermetallics having Al3Ti or Al3Zr crystal structures

Perturbed Angular Correlation Spectroscopy – A Tool for the Study of Defects and Diffusion at the Atomic Scale

Contact Info

Product

Resources

About

Temperature- and composition-driven changes in site occupation of indium solutes inGd1+3xAl2−3x

Cited by 19 publications

References 22 publications

Electric field gradients in the rare earth–aluminium compoundsRAl2andRAl3studied byForker1, Presa2 2007Phys. Rev. B

Electric field gradients in the rare earth–aluminium compoundsRAl2andRAl3studied byForker1, Presa2 2007Phys. Rev. B

Site preferences of indium impurity atoms in intermetallics having Al3Ti or Al3Zr crystal structures

Perturbed Angular Correlation Spectroscopy – A Tool for the Study of Defects and Diffusion at the Atomic Scale

Contact Info

Product

Resources

About

Electric field gradients in the rare earth–aluminium compoundsRAl2andRAl3studied by
Forker
¹
,
Presa
²

2007
Phys. Rev. B

Electric field gradients in the rare earth–aluminium compoundsRAl2andRAl3studied by
Forker
¹
,
Presa
²

2007
Phys. Rev. B