Ionic exchange and the local structure in the HfO2/Ho2O3 system studied by PAC spectroscopy

Experimental and First-Principles Theoretical Study of Structural and Electronic Properties in Tantalum-Doped In2O3 Semiconductor: Finding a Definitive Hyperfine Interaction Assignment

“…The two last ratios are larger than the crystallographic relative abundance of sites C and D in the bixbyite structure (3:1). The deviations from the value f C / f D = 3, which would correspond to a homogeneous population of the cationic sites by the TDPAC probe, are consistent with the variations previously observed in other isomorphous oxides. , The present experimental value points to a preference of the 181 Hf atoms for the asymmetric site C, in perfect agreement with the site preference predicted by the FP-APW+lo total energy calculations of Hf atoms localized at each cationic site of In 2 O 3 , presented in section III…”

“…The corresponding hyperfine parameters for all relevant spectra are listed in Table . It is well-known that the thermal annealing treatments following ion implantation remove the radiation damage and favor the replacement of host cations by TDPAC probes. ,, Considering this, the initial interaction assignment was done based on the relative abundance of both inequivalent cations sites of the bixbyite structure and the intensities of the obtained hyperfine interactions. So, the dominant hyperfine interaction was assigned to probes localized at cationic site C, and the minority interaction to probes localized at site D. With these assignments, the axially symmetric interaction is in agreement with the axial symmetry of site D. Even though V 33 D is not twice as large as V 33 C as in the rest of 181 Ta-doped and 111 Cd-doped bixbyites , V 33 D is still larger than V 33 C .…”

“…The deviations from the value f C /f D = 3, which would correspond to a homogeneous population of the cationic sites by the TDPAC probe, are consistent with the variations previously observed in other isomorphous oxides. 12,62 The present experimental value points to a preference of the 181 Hf atoms for the asymmetric site C, in perfect agreement with the site preference predicted by the FP-APW +lo total energy calculations of Hf atoms localized at each cationic site of In 2 O 3 , presented in section III.B. It should be noted here that the V 33 values decrease when the sample is measured at high temperature, in particular that corresponding to the asymmetric site C (7%), effect that could be attributed to the lattice expansion.…”

Substitutional Ta-doping in Y2O3 semiconductor by sol-gel synthesis: experimental and theoretical studies

“…For these reasons, in order to extend the useful range of the PAC spectroscopy, alternative and low-cost ways to prepare samples have been investigated mainly in the last decade. Among them, we can include those based in solid-state reactions between oxides [26,27] or the chemical precipitation method [28]. These alternative methods have shown their capability to successfully introduce the 181 Ta probe nuclei in a host matrix, nevertheless, the corresponding PAC experiments usually need additional supporting evidence to reach a complete interpretation of the complex spectra they give.…”

“…These alternative methods have shown their capability to successfully introduce the 181 Ta probe nuclei in a host matrix, nevertheless, the corresponding PAC experiments usually need additional supporting evidence to reach a complete interpretation of the complex spectra they give. Information of this kind includes parallel control experiments, additional data obtained from compounds with the same crystal structure, or an accurate theoretical prediction for the hyperfine properties [27,[29][30][31]. Considering all these facts, a current challenge is to find an affordable and effective way to perform the PAC probe doping of host structures.…”