Sn-vacancy defects in GaP

Complex¹¹⁹Sn-vacancy defects in GaP have been studied by Mössbauer-emission spectroscopy on the 24-keV γ radiation of¹¹⁹Sn. The defects were created by ion implantations of radioactive¹¹⁹In⁺ and¹¹⁹Sb⁺, which in their decays both populate the Mössbauer state of¹¹⁹Sn. The radiogenic¹¹⁹Sn-vacancy defects are proposed to consist of substitutional¹¹⁹Sn on Ga or P sites, respectively, associated with (P or Ga) vacancies.     

Tin U ?-centers formed through nuclear transformations in vitreous arsenic sulfides and selenides

It has been shown using the M?ssbauer emission spectroscopy for isotope ¹¹⁹Sn that impurity tin atoms formed after the radioactive decay of ¹¹⁹Sb atoms in vitreous arsenic sulfide and selenide are localized in arsenic sites and play the role of two-electron centers with negative correlation energy. The most of daughter ^119m Sn atoms formed after the radioactive decay of the ^119m Te atoms in glasses are arranged in chalcogen sites; they are electrically inactive. Considerable recoil energy of daughter atoms in the case of decay of ^119m Te leads to the appearance of ^119m Sn atoms shifted from chalcogen sites.     

Study of the excited states of119Sn by the decay of119g+m In

The decay of^119g+m In to the excited states of¹¹⁹Sn was investigated.¹¹⁹In was produced by the¹²⁰Sn(γ,p)¹¹⁹In reaction on an enriched SnO₂ target. The isomeric transition of 311.25 keV to the¹¹⁹In ground state was observed. In the beta decay of^119m In excited states at 23.9, 920.5, 921.4, 1089.0, 1187.9 and 1249.6keV in¹¹⁹Sn withJ ^π values of 3/2⁺, 3/2⁺, 5/2⁺, 5/2⁺, 3/2⁺ and 1/2⁺ respectively, are fed. In the decay of the¹¹⁹In ground state only the 7/2⁺ level in¹¹⁹Sn at 787.0 keV is fed.     

119Sn Mössbauer study of the implantation behaviour of119In,119Sn,119mSn,119Sb and119mTe ions in SiC

The implantation behaviour of stable¹¹⁹Sn⁺ ions and radioactive¹¹⁹In⁺,^119mSn⁺,¹¹⁹Sb⁺ and^119mTe⁺ ions in SiC has been investigated by, respectively, conversion-electron Mössbauer spectroscopy on the 24 keV transition of¹¹⁹Sn, and by Mössbauer emission spectroscopy on the 24 keV radiation emitted by the¹¹⁹Sn daughter after the decays of the radioactive isotopes. The Mössbauer spectra could be decomposed in most cases into two groups of lines, one originating from¹¹⁹Sn atoms on substitutional Si sites, the other from various Sn-vacancy complexes distinguished by their Mössbauer parameters. Annealing experiments reveal a strong dependence of the structure of the defects and the formation and annealing kinetics on the chemical nature of the impurities. Defects formed in 297 K implantations with^119mSn and¹¹⁹Sb anneal above 500 C, resulting in a preferential location of the impurities on substitutional Si sites, whereas^119mTe atoms are efficient defect-trapping centres and no stable, substitutional fraction is observed on either lattice site. Possible structures for the Sn-vacancy complexes are discussed and comparison is made to similar defect complexes in group IV and in III–V semiconductors.     

Mössbauer study of the formation of impurity-vacancy complexes in copper

The formation of impurity-vacancy complexes has been studied with ion-implanted radioactive¹¹⁹Xe and its decay products, which populate the¹¹⁹Sn Mössbauer state via the decay chain¹¹⁹Xe→¹¹⁹I→¹¹⁹Te→¹¹⁹Sb→¹¹⁹Sn. The results of these implantations arecompared to those from earlier¹¹⁹In or Sbimplantations.     

Hyperfine fields for119Sn in laves phases Rt2 (R=rare earth: T=Fe,Co, Ni)

The hyperfine fields acting on¹¹⁹Sn nuclei in the RT₂ (R=Sm?Lu; T=Fe, Co, Ni) have been measured by Mössbauer spectroscopy. It has been found that the hyperfine fields acting on¹¹⁹Sn nuclei in the RT₂ compounds are changed at some electronic occupation of the 4f shell of the R-component. The occupation of 4f shell is varied with the T-component. The sharp change of the hyperfine fields are connected with the change of the electronic band structure.     

First observation of the beta decay of117Pd and the discovery of a new isotope119Pd

In this paper we wish to report the first direct observations of the beta decays of¹¹⁷Pd and of a new isotope¹¹⁹Pd. The measuredβ-half-life is 4.3±0.3 s for¹¹⁷Pd. For¹¹⁹Pd, the existence of two beta-decaying states with the same half-life but of opposite parity cannot be excluded. The measured half-life for¹¹⁹Pd is 0.92±0.13 s. The observed beta half-lifes are in good agreement with the QRPA predictions. The observed level structure of¹¹⁷Ag and¹¹⁹Ag are discussed in the frame of the level systematics of the known odd Ag isotopes closer to stability.     

Mössbauer measurement of the hyperfine magnetic field AT sp site in Heusler alloys Rh2 Mn Z (Z=In and Sb)

We have investigated the systematics of hyperfine magnetic field on a fixed probe at the Z-site in Heusler alloys Rh₂MnZ as the valence of Z (sp element) is varied. The hmf on¹¹⁹Sn in Rh₂MnIn_.98 ¹¹⁹Sn₀₂ has been measured at 293K and 77K. In Rh₂Mn_1.12Sb_.86 ¹¹⁹Sn_.02 the hmf on¹²¹Sb has been measured at 77 K, and on¹¹⁹Sn at 293 K and 77 K. The results are compared with the hmf on¹¹⁹Sn in Rh₂Mn Ge_.98 ¹¹⁹Sn_.02 Rh₂Mn Sn, and Rh₂Mn Pb_.98 ¹¹⁹Sn_.02.Supported by the University Research Council, University of CincinnatiSupported by the Natural Sciences and Engineering Research Council of Canada     

Tin-doped spinel-related oxides of composition M3O4 (M = Mn, Fe, Co)

Tin-doped compounds of spinel-related M₃O₄ (M = Fe, Mn, Co) have been studied by ¹¹⁹Sn and ⁵⁷Fe Mössbauer spectroscopy in the temperature range of 20–600 K. The ¹¹⁹Sn Mössbauer spectra recorded down to 20 K from the non-iron-containing compounds of Co₃O₄ and Mn₃O₄ contained only doublets showing no transfer of magnetic properties from cobalt or manganese to the dopant tin ions. In contrast, the tin-doped-(FeCo)₃O₄ and (FeMn)₃O₄ gave ¹¹⁹Sn and ⁵⁷Fe Mössbauer spectra, which showed magnetic hyperfine interactions. The Curie temperature has been estimated for the former sample.     

Mössbauer study of donor-hydrogen complexes in silicon

Mössbauer spectroscopy has been applied to study the Sb-H complex in Si, using the 23.9 keV transition of¹¹⁹Sn populated in the decay of¹¹⁹Sb. Hydrogen was introduced into a well annealed Si crystal, previously implanted with¹¹⁹Sb ions. The relative intensity of the H-associated line reaches 26% at the highest hydrogen dose of 10¹⁶ cm^?2. The Sb?H complexes dissociate around 440 K. No Sb?H complexes were observed in material that remained p-type after implantation of¹¹⁹Sb. The implications of these measurements for the structure of the Sb?H complex and for the charge states of the diffusing hydrogen are discussed.     

Cross-sections of isomeric state excitation of the 119Te and 121Te nuclei in (γ, n) reactions in an energy range of 9–20 MeV

The dependence of isomeric yield ratios upon the maximum bremsstrahlung gamma-quanta energy for the ¹²⁰Te(??, n)^119m,g Te and ¹²²Te(??, n)^121m,g Te reactions within an energy range of the giant dipole resonance is investigated. Cross-sections of excitation of metastable states with J ^?? = 11/2^? of the ¹¹⁹Te and ¹²¹Te nuclei are obtained. Experimental data are compared with computation results obtained using the TALYS-1.2 software package.     

High-resolution study of the 118Sn(d,p)119Sn reaction at 17 MeV

Energy levels in ¹¹⁹Sn up to 4.75 MeV excitation have been studied with the ¹¹⁸Sn(d, p)¹¹⁹Sn reaction at an incident deuteron energy of 17 MeV. The scattered particles were analysed by a magnetic spectrograph and detected in nuclear emulsions with a resolution of ≈ 9 keV. Seventyseven energy levels were identified. Angular distributions were compared to DWBA predictions allowing the identification of transferred angular momenta and the determination of spectroscopic factors for 49 states. The results obtained are compared with pairing theory and the weakcoupling model.     

Mössbauer study of119Sb-vacancy complexes in Mo and Pt

The formation and subsequent annealing of various¹¹⁹Sb-vacanoy complexes has been studied in Pt and Mo foils. The defects were produced either during ion implantation of¹¹⁹sb or during low-temperature light-ion bombardment. Parameters measured with the 24 keV Mössbauer transition in¹¹⁹Sn are reported for several complexes and discussed in relation to results from other microscopic methods.     

Defect annealing in Sb/Sn implanted diamond investigated with Sn Mössbauer spectroscopy

The annealing of defects in Sb/Sn implanted diamond has been studied in ¹¹⁹Sn Mössbauer spectroscopy following the implantation of radioactive parent isotopes ¹¹⁹Xe and ^119mSn. Our results show that after annealing above 1300 K, 40% of the implanted ions are located at or near regular sites in the lattice. Significant implantation induced defects however remain.     

Signature inversion in the yrare band of <Superscript>119</Superscript>Xe

Excited states of the ¹¹⁹Xe nucleus have been studied by using in-beam γ-ray spectroscopy with the ¹⁰⁷Ag ( ¹⁶O, p3n) ¹¹⁹Xe fusion-evaporation reaction at a beam energy of 85 MeV. The level scheme of ¹¹⁹Xe has been derived from γ-γ coincidence and γ-γ angular correlation analyses. We have, for the first time, established the second negative-parity favored and unfavored states built on the 11/2^- state, namely the yrare rotational bands in ¹¹⁹Xe. In contrast to the behavior of the yrast bands where the favored states are lying lower in energy, the yrare favored states were observed to lie above the unfavored band. Such a signature inversion in ¹¹⁹Xe is changed to be normal at I = 12?. Received: 8 January 2002 / Accepted: 18 April 2002     

Magnetic hyperfine fields of vacancy-associated119Sn in ion-implanted nickel

Magnetic hyperfine fields of¹¹⁹Sn impurity defects in nickel have been investigated by Mössbauer emission spectroscopy. Radioactive¹¹⁹Xe isotopes were implanted, annealing was performed after¹¹⁹Xe had decayed to¹¹⁹Sb. At least five different components with well-defined magnetic hyperfine fields, isomer shifts and Debye temperatures are identified in the rather complex spectra. One of these (B=2T) is known to be due to substitutional Sn. The hyperfine fields of the other components are pronouncedly larger (B=9T, B=15T, and B=17T, respectively, for single crystals). These defects are proposed to be Sn-multivacancy defects.     

Solid-State Si, Cd, Sn, and P NMR Studies of II-IV-P2 Semiconductors

Solid-state ²⁹Si, ¹¹³Cd, ¹¹⁹Sn, and ³¹P MAS NMR spectra are reported on a series of II-IV-P₂ compounds. In favorable cases (e.g., high degree of crystallinity, low concentration of unpaired electrons), well-defined spectra, with sharp lines for each specific nearest-neighbor configuration, are observed; in such cases, expected J coupling patterns are also seen. High-resolution solid-state NMR studies of this type provide useful information on structure (disorder), doping, and electron-mediated coupling in semiconductor systems.     

Study of neutrino-recoil produced point defects in InSb by119Sn Mössbauer spectroscopy

We have utilized the electron-capture decay of¹¹⁹ Te to¹¹⁹Sb to produce isolated single Frenkel pairs in InSb. This effect is caused by the neutrino emission in the decay process which imparts a monoenergetic recoil of 12 eV to the¹¹⁹Sb atoms, thereby displacing about 20% of them to interstitial sites. Two distinct interstitial components can be observed. The process is traced by Mössbauer emission spectroscopy following the decay of¹¹⁹Sb to¹¹⁹Sn. The displacement thresholdE _d is confined to 6 eV<E _d <12 eV from auxiliary experiments employing^119mTe isotopes.     

Defect structures of ion-implanted α-tin

Single crystalline and polycrystalline -tin has been implanted at room temperature with 80-keV ions of radioactive^119m Sn,¹¹⁹Sb, and^119m Te. The radioactive nuclei decay to the Mössbauer level of¹¹⁹Sn. Mössbauer spectra of the emitted 24-keV radiation have been measured for different source temperatures by resonance counting techniques. Five individual lines in the spectra are characterized mainly by their isomer shifts and Debye temperatures. From these parameters the radiogenic¹¹⁹Sn atoms are concluded to be located in regular substitutional and interstitial lattice sites and in defect complexes. Simple models for the defects are proposed: A Sn-vacancy pair consists of Sn atoms on (nearly) substitutional sites with a dangling bond into an adjacent vacancy. In a complex oxygen-containing defect the Sn atoms have approximately a 5s ² configuration withp-bonds to two nearest neighbour atoms. Sn atoms, having an atomic 5s ² 5p ² configuration and large vibrational amplitudes, are concluded to be in non-bonding regular interstitial sites. For special implantation conditions minor fractions of SnO₂ molecules are formed in the bulk. The interstitial¹¹⁹Sn and the¹¹⁹Sn-vacancy pairs are proposed to represent elementary point defects in -tin. Conclusions are also drawn concerning the lattice location and the defects created in the implantation process of the implanted parent isotopes.     

Radiogenic Sn defects in ion-implanted CdTe

Radioactive^119mCd⁺ and¹¹⁹In⁺ ions have been implanted into CdTe single crystals at temperatures between 50–300K. Radiogenic defects formed with the daughter¹¹⁹Sn have been investigated by Mössbauer spectroscopy of the emitted 24 keV γ radiation. All Mössbauer spectra could be analysed consistently with three lines. These are proposed to be due to substitutional Sn on Cd sites in two different charge states and to Sn-vacancy complexes. The corresponding In-parent vacancy complexes anneal at 120K and above 300K.