Tdpac-Studies of Electric Field Gradients in Amorphous Metallic Systems

1980 ◽  
Vol 3 ◽  
Author(s):  
P. Heubes ◽  
D. Korn ◽  
G. Schatz ◽  
G. Zibold
Keyword(s):  
Electric Field ◽  
Structural Model ◽  
Electric Field Gradient Tensor ◽  
Correlation Technique ◽  
Relative Width ◽  
Electric Field Gradients ◽  
Gradient Tensor ◽  
Field Gradients ◽  
Time Differential ◽  
Metallic Systems

ABSTRACTThe time differential perturbed γ-γ angular correlation technique (TDPAC) is applied to the amorphous metallic systems Ga, Bi, In50Au50 and In80Ag20. The electric field gradient tensor probed by 111Cd nuclei shows a broad probability distribution with a relative width of 0.4 – 0.5 for all systems, as suggested by a continuous random structural model.

Electric Quadrupole Interaction at 181Ta in Isostructural Orthorhombic Cu8Hf3 and Cu8Zr3 Compounds

1998 ◽  
Vol 53 (6-7) ◽  
pp. 355-357
Author(s):  
P. Wodniecki ◽  
B. Wodniecka ◽  
A. Kulińska ◽  
A. Z. Hrynkiewicz
Keyword(s):  
Electric Field ◽  
Quadrupole Interaction ◽  
Perturbed Angular Correlation ◽  
Electric Quadrupole ◽  
Correlation Technique ◽  
Interaction Frequency ◽  
Electric Quadrupole Interaction ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Time Differential

Abstract The quadrupole interaction of 181Ta probes in isostructural Cu8Hf3 and Cu8Zr3 intermetallic compounds was studied in the temperature range 24 K -1100 K with the time-differential perturbed angular correlation technique. Two nonaxial electric field gradients corresponding to two nonequiv-alent hafnium or zirconium sites in the investigated structure were found. A linear decrease in the quadrupole interaction frequency with increase of temperature for the 8(d) sites was evidenced, while the vQ(T) dependence for the 4(c) sites is weaker and has a T3/2 character.

Geometrical Structure of Lattice Defect-Impurity Configurations Determined by TDPAC

1980 ◽  
Vol 3 ◽  
Author(s):  
M. Deicher ◽  
O. Echt ◽  
E. Recknagel ◽  
Th. Wichert
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Geometrical Structure ◽  
Perturbed Angular Correlation ◽  
Lattice Defect ◽  
Electric Field Gradient Tensor ◽  
Correlation Technique ◽  
Gradient Tensor ◽  
Defect Clusters ◽  
Microscopic Interpretation

ABSTRACTThe perturbed angular correlation technique (TDPAC) was applied to determine the orientation of the electric field gradient tensor induced by lattice defects at the probe 1l1In. The experimental results obtained for self-interstitials, vacancies and defect clusters in Cu, Ag and Au are shown and their microscopic interpretation is discussed.

Impurity Cationic-Site Population and Electric-Field Gradient Dependence on Ionic Size in Bixbyites Sesquioxides Implanted With 181Hf → 181Ta

1998 ◽  
Vol 12 (20) ◽  
pp. 819-827 ◽  
Author(s):  
M. Rentería ◽  
A. G. Bibiloni ◽  
F. G. Requejo ◽  
A. F. Pasquevich ◽  
J. Shitu ◽  
...  
Keyword(s):  
Electric Field ◽  
Perturbed Angular Correlation ◽  
Lattice Parameter ◽  
Correlation Technique ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Cationic Site ◽  
Small Lattice ◽  
Ionic Size ◽  
Site Population

The Perturbed-Angular-Correlation technique was used to study the impurity cationic-site population and electric-field gradients in scandium and samarium sesquioxides implanted with 181 Hf → 181 Ta . We found a departure of the tantalum (hafnium) relative occupancy of the crystallographic sites C and D in the bixbyite structure from the natural abundance of the sites, in the case of scandium sesquioxide, that could be explained in terms of the small lattice parameter of this sesquioxide. A similar behavior occurs in the case of indium sesquioxide. In the rest of the bixbyites measured with 181 Ta , f D /f C remains nearly constant and close to the crystallographic abundance, which is only reached in the case of Sm 2 O 3, the sesquioxide with the largest lattice parameter. Additionally, we confirm a jump in the values of νQ( Ta ) for sites C and D that takes place for a ≤ 1:012 nm, that is for lattice parameters smaller than that of ytterbium sesquioxide.

scholarly journals Electric Field Gradients at the In Site in Au-In Compounds

1998 ◽  
Vol 53 (6-7) ◽  
pp. 349-354 ◽  
Author(s):  
P. Wodniecki ◽  
A. Kulińska ◽  
B. Wodniecka ◽  
A. Z. Hrynkiewicz
Keyword(s):  
High Temperature ◽  
Electric Field ◽  
Angular Correlation ◽  
Perturbed Angular Correlation ◽  
High Temperature Phase ◽  
Correlation Technique ◽  
Temperature Phase ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Temperature Dependences

Abstract The quadrupole interaction in Au-In compounds of different stoichiometrics was studied with the perturbed angular correlation technique. The electric field gradients at 111Cd probes were measured and the temperature dependences of the quadrupole frequencies were determined. A new high temperature phase of Auln above 630 K and a new metastable modification of Au7In3 were found.

Formation of In-Cu Pairs in Silicon During Chemomechanical Polishing

1989 ◽  
Vol 163 ◽  
Author(s):  
Th. Wichert ◽  
R. Keller ◽  
M. Deicher ◽  
W. Pfeiffer ◽  
H. Skudlik ◽  
...  
Keyword(s):  
Electric Field ◽  
Angular Correlation ◽  
Correlation Technique ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Acceptor Atom

AbstractUsing the perturbed γγ angular correlation technique (PAC) the pairing of Cu with the radioactive acceptor atom 111In in Si is detected. Because of the identity of the electric field gradients the so-called X defect, observed after chemomechanical polishing of Si wafers and known of neutralizing acceptor atoms in Si, is identified as a Cu atom. It is also shown that as-delivered Si wafers already contain Cu atoms which neutralize acceptor atoms if the wafers are annealed at 1173 K.

Quadrupole interaction of 181 Ta in Hf compounds

1969 ◽  
Vol 311 (1504) ◽  
pp. 197-206 ◽  
Keyword(s):  
Electric Field ◽  
Field Gradient ◽  
Quadrupole Interaction ◽  
Electric Quadrupole ◽  
Electric Quadrupole Interaction ◽  
Electric Field Gradients ◽  
Correlation Studies ◽  
Field Gradients ◽  
Yield Information ◽  
Time Differential

Time-differential angular correlation studies of the electric quadrupole interaction of 181 Ta in various Hf compounds are presented. Methods for the analysis of the time spectra are discussed. The experiments yield information on the strength of the quadrupole interaction, and on the axial asymmetry and distribution of the field gradient. Electric field gradients V zz are derived for 181 Ta in Hf metal, HfO 2 , and (NH 4 ) 2 HfF 6 .

A Simple Model to Explain 19F-TDPAD Amplitude Characteristics

1992 ◽  
Vol 47 (1-2) ◽  
pp. 389-394
Author(s):  
H.-R. Blank ◽  
M. Frank ◽  
J. Heindl ◽  
M. Kaltenhäuser ◽  
H. Köchner ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Simple Model ◽  
Electric Field ◽  
Kinematic Model ◽  
Electric Field Gradients ◽  
Strong Reduction ◽  
Field Gradients ◽  
Fluorine Compounds ◽  
Time Differential ◽  
Amplitude Characteristics

AbstractSince many years the 19F-TDPAD method (TDPAD = time differential perturbed angular distribution) has been used to investigate electric field gradients in fluorine compounds. In these experiments always a strong reduction of the observed interaction amplitudes is observed. To explain these characteristics, a simple kinematic model is suggested.

A Comparative Time Differential Perturbed Angular Correlation Study of the Nuclear Quadrupole Interaction in HfF4·HF·2H2O Using 180mHf and 181Hf(β–)181Ta as Nuclear Probes: Is Ta an Innocent Spy?

2009 ◽  
Vol 64 (1-2) ◽  
pp. 103-111 ◽  
Author(s):  
Tilman Butz ◽  
Satyendra K. Das ◽  
Yurij Manzhur
Keyword(s):  
Electric Field ◽  
Frequency Distribution ◽  
Quadrupole Interaction ◽  
Nuclear Quadrupole Interaction ◽  
Electric Field Gradients ◽  
Rapid Loss ◽  
Field Gradients ◽  
Small Admixture ◽  
Time Differential ◽  
Nuclear Quadrupole

We report on a comparative study of the nuclear quadrupole interaction of the nuclear probes 180mHf and 181Hf(β −)181Ta in HfF4・HF・2H2O using time differential perturbed angular correlations (TDPAC) at 300 K. For the first probe, assuming a Lorentzian frequency distribution, we obtained ωQ= 103(4) Mrad/s, an asymmetry parameter η = 0.68(3), a linewidth δ = 7.3(3.9)%, and full anisotropy within experimental accuracy. For the second probe, assuming a Lorentzian frequency distribution, we obtained three fractions: (1) with 56.5(7)%, ωQ= 126.64(4) Mrad/s and η = 0.9241(4) with a rather small distribution δ = 0.40(8)% which is attributed to HfF4・HF・2H2O; (2) with 4.6(4)%, ωQ = 161.7(3) Mrad/s and η = 0.761(4) assuming no line broadening which is tentatively attributed to a small admixture of Hf2OF6・H2O; (3) the remainder of 39.0(7)% accounts for a rapid loss of anisotropy and is modelled by a perturbation function with a sharp frequency multiplied by an exponential factor exp(−λ t) with λ = 0.55(2) ns−1. Whereas the small admixture of Hf2OF6・H2O escapes detection by the 180mHf probe, there is no rapid loss of roughly half the anisotropy as is the case with 181Hf(β −)181Ta. This loss could in principle be due to fluctuating electric field gradients originating from movements of nearest neighbour HF adducts and/or H2O molecules after nuclear transmutation to the foreign atom Ta which are absent for the isomeric probe. Alternatively, paramagnetic Ta ions could lead to fluctuating magnetic dipole fields which, when combined with fluctuating electric field gradients, could also lead to a rapid loss of anisotropy. In any case, Ta is not an “innocent spy” in this compound. Although 180mHf is not a convenient probe for conventional spectrometers, the use of fast digitizers and software coincidences would allow to use all γ -quanta in the stretched cascade which would greatly improve the efficiency of the spectrometer. 180mHf could also serve as a Pu analogue in toxicity studies.

Sign in / Sign up

Export Citation Format

Share Document