TDPAC studies of internal AgIn alloy oxidation

The internal oxidation of dilute AgIn alloys in open air versus In concentration and oxidation temperature was investigated by the TDPAC technique. The¹¹¹In interaction described by the broad quadrupole frequencies distribution aroundv _Q = 115 MHz and =0.5–0.7 was observed and interpreted as due to nonstoichiometric In–O_X cluster formation. For higher temperatures and more concentrated alloys additionally quasiunique frequencyv _Q 157 MHz with 0.28 was evidenced and ascribed to¹¹¹In interaction inside In₂O₃ precipitates. The internal oxidation under reduced oxygen pressures was studied and the thermal stability of the complex formed was tested. The effect of surface preparation on internal oxidation was observed.     

The Ag−In intermetallic compound formation from Ag and In electrodeposited layers observed by PAC

The PAC method was applied to study the intermetallic compound formation at Ag−In interfaces. The electrodeposited Ag−In layers of different Ag: In atomic ratios were prepared and isochronal annealing program was performed. For the comparison the bulk Ag₇₅In₂₅ and Ag₆₆In₃₄ specimens were examined. The Ag₂In and AgIn₂ compounds were detected and the quadrupole hyperfine interaction parameters for¹¹¹In in Ag₂In were measured as υ_Q107.9(3) MHz and η=0.48 (2).     

PAC study of compound formation in the In-Pt system

The perturbed angular correlation technique was applied to measure the quadrupole interaction parameters of¹¹¹Cd at the In sites in electroplated In/Pt bilayers successively annealed at elevated temperatures. The consecutive creation of different compounds was evidenced by means of their PAC signal. The In₇Pt₃ andIn₃Pt₂ compounds were identified by comparison of the observed quadrupole interaction parameters with those measured for In-Pt bulk samples with defined stoichiometry.     

TDPAC studies of the kinetics of diffusion-limited reactions in dilute AgPt alloy

The TDPAC studies of In-Pt pairs formation in dilute AgPt alloy in nonequilibrium state are performed. The concentration of the In-Pt complexes is measured for different annealing temperatures and times. The results are compared with calculations based on the model of diffusion controlled bimolecular reactions. The conclusions about diffusion enhancement due to radiation damage and the interaction of impurities with radiation defects are drawn.     

Intermetallic compound formation at the In-Pd interface investigated with111In local probes

The TDPAC technique was applied to study the formation of In-Pd compounds in bilayer electrodeposited sample doped with the radioactive¹¹¹In. Subsequent isochronal annealings at increasing temperatures caused the Pd diffusion into the In layer reflected in the quadrupole interactionR(t) curves. The appearing new unique frequencies indicate the formation of ordered In₃Pd, In₃Pd₂ andInPd₂ phases in the sample. The identification of this In-Pd compounds was based on the PAC measurements for bulk In-Pd samples with defined stoichiometry.     

Hyperfine Interaction of 111Cd in Fe3Sn Compound

The hyperfine interaction of ¹¹¹Cd in ferromagnetic Fe₃Sn compound was investigated by TDPAC in the paramagnetic region and below the Curie temperature. The results are compared with hyperfine magnetic fields and EFGs on ¹¹¹Cd and ¹¹⁹Sn in other stoichiometric Fe–Sn phases. This revised version was published online in September 2006 with corrections to the Cover Date.     

Perturbed angular correlation experiments on111In in oxidized AgCd alloy

The hyperfine interaction of¹¹¹Cd probes in preoxidized and α-irradiated Ag_0.94Cd_0.06 alloy has been investigated by PAC measurements and compared with the results for pure Ag. Several probe atom sites were distinguished and characterized by their hyperfine parameters and temperature evolution. The different behavior of In-oxygen and In-oxygen-vacancy complexes in AgCd and Ag was found and discussed. A considerable influence of the irradiation temperature and sample thickness on the different In-oxygen-vacancy complexes formation was evidenced. The parameters of¹¹¹Cd quadrupole interaction measured during isochronal annealing studies in preoxidized and deuteron irradiated AgCd were very similar to the ones observed after α-irradiation.     

Oxidation of ZrAl and Zr3Al compounds studied by181Ta-PAC spectroscopy

Hyperfine Interactions - The perturbed angular correlation method was applied to follow the oxidation processes in ZrAl and Zr3Al intermetallic compounds. It was found that the limiting temperature...     

Electric quadrupole interaction at 111Cd and 119Sn in isostructural NiIn and CoSn compounds

The perturbed angular correlation technique and Mössbauer spectroscopy were applied to study the electric field gradient on ¹¹¹Cd and ¹¹⁹Sn probe atoms in isostructural NiIn and CoSn compounds. The ¹¹¹Cd PAC measurements performed in the temperature range 80--1100 K demonstrated the existence of two axially symmetric EFG's in each of the investigated compounds, related to the 2(d) and 1(a) probe sites in the B35 structure. A 1(a)-site preference for Cd probes in CoSn compound was observed. The temperature dependence of the quadrupole frequencies for ¹¹¹Cd in both compounds, interpreted in terms of the empirical model proposed by Christiansen et al.[1], follows a T^3/2 relation with different slope parameters for each of the observed frequencies. These results are combined with the data from the Mössbauer experiment. The ¹¹⁹Sn Mössbauer spectra taken at liquid nitrogen and at room temperatures showed two quadrupole split doublets with the intensity ratio 2:1 for CoSn and 8:1 for NiIn_0.99Sn_0.01sample, giving an evidence of 2(d)-site preference for tin atoms in NiIn. The EFG values measured on ¹¹⁹Sn are 2.5 to 4 times larger than those on ¹¹¹Cd nuclei, while the ratio of the respective Sternheimer antishielding factors is equal to 0.77. Within the limits of errors no differences were observed in the magnitude and temperature dependence of Debye--Waller factors for 2(d) and 1(a) ¹¹⁹Sn positions in CoSn and NiIn lattices.