In the II–VI compounds ZnTe and CdTe, tracer diffusion and perturbed angular correlation experiments revealed a hindered diffusion of Pd at elevated temperature in tellurium-rich material due to the formation of Pd-metal-vacancy complexes. In metal-rich n-type material, Pd distributes by diffusion over the entire sample volume. Additional group-V element implantation has different effects in ZnTe and CdTe: in metal-rich ZnTe, the Pd diffusion is hindered and complex formation at Pd is found; in metal-rich CdTe, the Pd diffusion seems to be unchanged and, in the case of N, a complex is formed at elevated temperatures interpreted as consisting of interstitial Pd and interstitial N.

In the II-VI compound ZnTe perturbed angular correlation and tracer diffusion experiments with the nuclear probe Pd-100/Rh-100 revealed the formation of a defect complex by the observation of a well-defined quadrupole interaction in tellurium-rich crystals. The defect complex is tentatively interpreted as a Pd A-centre with Pd on the chalcogen lattice site. Using the DLTS method no deep levels correlated to implanted palladium could be detected in the range of 0.2 to 0.8 eV above the valence band edge.

The local magnetic behavior of recoil-implanted isolated Sc ions has been studied in II–VI and other semiconducting compounds. In all cases nonmagnetic configurations were observed consistent with an empty d-shell of the Sc ion. Additionally a different influence of nearby defects on the Sc probe ion was observed in the various types of compound semiconductors.

Perturbed angular distribution (PAD) measurements were performed on Zn1−xMnxS (x = 0.05, 0.06, 0.10, 0.18, 0.21 and 0.23). In our PAD experiments recoil-implanted 54Fe ions were used as nuclear probes. By the local magnetic behaviour of the isolated 54Fe nuclei we obtained information on the probe environment. The crystal having the lowest manganese concentration (x=0.05) shows only one hyperfine component. The temperature dependence of this component is the same as in that case of pure ZnS. For samples with concentrations x⪖0.06 two additional hyperfine components are observed. One of them is attributed to β- or γ-MnS clusters, respectively. The other additional component occurs for crystals having Mn-concentrations x⪖0.10. The behaviour of this component is similar to the one observed with pure α-MnS. From our data we conclude that the additional components observed with Mn concentrations x⪖0.06 are due to the formation of different types of MnS clusters. Our experimental findings are compared with the data of magnetic susceptibility, photoluminescence and EPR.

The local magnetic behaviours of isolated Fe and Ni impurities in the II-VI semiconductors ZnS and ZnTe have been studied directly after recoil implantation. From the measured magnetic properties, which are detected by the observation of the perturbed angular distribution, orbital contributions to the hyperfine field as well as contribution from spin magnetism are found to be present at both impurities. The interpretations on the basis of the intermediate ligand field model suggest that Fe and Ni ions are found to exist in 2+ and in 1+ states and that electronic excitations may play a significant role even microseconds after the implantation.

The local magnetic behavior of isolated Fe and Ni ions has been determined in ZnS and other semiconducting compounds via the hyperfine interaction at the nucleus. It is concluded that in ZnS Fe ions are observed in the 1+ state while Ni is found in two states, the 1+ state, observed as a magnetic component, and, less abundant, the 2+ state in a nonmagnetic configuration. In InP and other semiconducting compounds, Ni is typically found in a nonmagnetic state.

The neutron-deficient nuclei100,101Cd were identified for the first time in — beam following the reactions58Ni +46,48Ti and58Ni +50Cr at 230 MeV and 245 MeV bombarding energy of the58Ni beams. Theγ-decay of the isotopes100,101,102Cd was studied inpγ, ppγ,nγ, nnγ, andnγγ prompt and delayed coincidence spectra. Isomers were found with spin and half life {ie1-01}=8+, T1/2=52(5) ns in100Cd, {ie1-02}=(19/2+), T1/2=4.6(4) ns in101Cd and {ie1-03}=8+, T1/2=56(4) ns in102Cd. In a PAD experiment theg-factor of the {ie1-04}=8+ isomer in100Cd was measured to be g=1.24(6). Using the reaction36Ar +70Ge at 135 MeV energy of the36Ar beam, theg-factor and the quadrupole moment of the {ie1-05}=8+ isomer in102Cd were measured to be g=1.29(3) and Q=87(10) fm2, respectively. The spectroscopic results are discussed within a shell model approach using a100Sn core, which accounts well for the electromagnetic properties of the proton aligned isomers. The structure of the spherical neutron states, dominated by the close lying vd5/2, g7/2 orbitals, and the gradually developing quadrupole collectivity are reproduced by the shell model calculations.

Excited states in97Ag have been identified for the first time following the reactions46Ti(58Ni,α p 2n and64Zn(36Ar,p 2n. The population cross sections were 1.0(5) mb and 0.7(3) mb, respectively. Theγ-decay of the seniorityΝ=3 states below theIπ=(17/2−) and (21/2+) isomers was investigated. In a search for short lived isomers half lives oft1/2=5(2) ns and 2.5(5) ns were found in theN=50 isotones97Ag,Iπ=(17/2−) and/or (21/2+) and95Rh,Iπ=(21/2+). A new isomer was identified in97Pd,Iπ=17/2+ witht1/2=2.3(5) ns. The implication of the three-proton hole spectrum in100Sn for the empirical residual interaction and shell model predictions is discussed.

We have searched for neutrons from a Pd-electrode loaded with deuterium in electrolysis setups similar to those of Fleischmann and Pons [1] and Jones et al. [2]. Within the sensitivity of our neutron detection system corresponding to a neutron source strength of 5 x 10- 2 neutrons/s we did not find any neutrons due to ‘cold nuclear fusion’. We emphasize the necessity of using several independent neutron detectors.

We have searched for neutrons from a Pd-electrode loaded with deuterium in electrolysis setups similar to those of Fleischmann and Pons [1] and Jones et al. [2]. Within the sensitivity of our neutron detection system corresponding to a neutron source strength of 5 x 10− 2 neutrons/s we did not find any neutrons due to ‘cold nuclear fusion’. We emphasize the necessity of using several independent neutron detectors.

The magnetic hyperfine fields at isolated Ni impurities in Pd and Pd-Pt alloys were studied with the perturbed-angular-distribution (PAD) method by measuring the temperature, magnetic field, and concentration dependence of the nuclear-spin Larmor precession of isomeric states in $^{63}\mathrm{Ni}$. The recoil-implanted Ni nuclei, as products of heavy-ion nuclear reactions, are present in extreme dilution (<1 ppm) in the hosts. The positive Larmor frequency shift (Knight shift) observed for Ni impurities in Pd follows a Curie-Weiss-like temperature dependence with a large Curie constant indicating a giant moment behavior. For Ni impurities in the Pd-Pt alloys a considerable positive shift remains even at 30 at. % Pt content. The variation of the shift with Pt concentration and temperature reflects the variation of the Pd-Pt alloy susceptibility. The different contributions to the hyperfine field could be differentiated by comparing the Knight shift for Ni in Pd with its susceptibility contribution obtained from extrapolated susceptibility measurements in dilute Pd-Ni alloys. The negative core-polarization field of the impurity spin moment is compensated for by a transferred hyperfine field correlated with the host polarization in the neighborhood of the impurity. The remaining positive hyperfine field is due to a weak orbital moment of 0.3${\ensuremath{\mu}}_{B}$ at the impurity site. The values obtained for the different contributions are compared with results of the Korringa-Kohn-Rostoker--coherent-potential-approximation calculations for concentrated Pd-Ni alloys extrapolated to the dilute limit.

The neutron deficient nucleus96Pd, four proton holes below the doubly magic100Sn, has been studied in the reaction64Zn (36Ar, 2p 2n). Innγ andγγ coincidences levels up to 7 MeV excitation energy were established, and a new neutron core-excited isomer with T1/2=35(4)ns and g=0.83 (5) was identified. A detailed shell model study yields excellent agreement for states within the π(p1/2,g9/2) configuration space but fails to reproduce the isomerism andg-factor for the core-excited state.

Etude du comportement magnetique local d'impuretes d'elements de transition isolees dans des metaux: localisation des electrons 3d dans des reseaux hotes formes de metaux alcalins, interactions magnetiques des atomes d'impurete sur differents sites du reseau

The neutron deficient nucleus96Pd, four proton holes below the doubly magic100Sn, has been studied in the reaction64Zn (36Ar, 2p 2n). Innγ andγγ coincidences levels up to 7 MeV excitation energy were established, and a new neutron core-excited isomer with T1/2=35(4)ns and g=0.83 (5) was identified. A detailed shell model study yields excellent agreement for states within the π(p1/2,g9/2) configuration space but fails to reproduce the isomerism andg-factor for the core-excited state.

The magnetic field has been determined on F in CuO in the ordered phase. For magnetic fluctuations above the ordering temperature lower limits have been obtained for CuO and La2−χSrχCuO4 with x=0.07.

The magnetic field has been determined on F in CuO in the ordered phase. For magnetic fluctuations above the ordering temperature lower limits have been obtained for CuO and La 2−χ Sr χ CuO 4 with x=0.07.

The local susceptibilities and the 3d spin dynamics of isolated nickel ions in various alkali-element hosts have been measured, utilizing the perturbed \ensuremath{\gamma}-ray distribution method after recoil implantation. In the heavy alkali-metal hosts, Cs, Rb, and K, the local susceptibilities of the isolated Ni ions irrespectively show the temperature behavior of a fully localized spin-orbit-coupled 3${\mathrm{d}}^{9}$ configuration. Clear host dependence of the magnetic behavior is seen in the spin-fluctuation rates which increase with decreasing host volume. In Na, the magnetic behavior drastically deviates from that of the purely ionic configuration, and Ni ions in Li as well as in Ca and Ba hosts are nonmagnetic.

Determination de la dependance avec la temperature, le champ magnetique et la concentration, du champ magnetique hyperfin de Ni dans Pd et PtPd a l'aide de la methode de correlation angulaire perturbee

The magnetic behaviour of isolated nickel and copper impurities in various alkali elements is studied via hyperfine field measurements using the PAD-method.The Ni impurities exhibit strong local moments in nearly all alkali metals, but are non-magnetic in Li and in the alkali earths Ba and Ca.The temperature dependence of the paramagnetic enhancement factor of Ni in Rb and K nicely follows a Curie-Weiss-law.The extreme large positive saturation hyperfine field extracted from the Curie constant can only be explained by a nearly unperturbed spin-orbit coupled 3d9-configuration of localized 3d-electrons.For Ni in Na the paramagnetic enhancement factor is reduced and shows a maximum at room temperature.The Cu impurities in Cs exhibit non-magnetic behaviour which is expected from the most probable 3d1°configuration.