Lattice Location of Hf in Near-Stoichiometric LiNbO&lt;sub&gt;3&lt;/sub&gt;: RBS/Channeling and PAC Studies

Marques, J.G.; Kling, A.; Rebouta, L.; Silva, M.F. da; Melo, A.A.; Soares, J.C.; Serrano,; Diéguez, E.; Agulló‐López, F.

doi:10.4028/www.scientific.net/msf.248-249.395

Cited by 5 publications

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“…76) and in a congruent crystal doped with 6 mol% HfO 2 in the melt. 77 Codoping with K 2 O yields near-stoichiometric or stoichiometric crystals 7 although no K was found in the crystals by PIXE down to the detection limit of 100 ppm.…”

Section: Factors Affecting the Lattice Location Of Hfmentioning

confidence: 99%

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Lattice location of Hf and its interaction with other impurities in LiNbO3: a review

Marques

Lorenz

2014

Opt. Eng

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Abstract. Lithium niobate, LiNbO3, exists in a wide range of compositions, from congruent to stoichiometric. Undoped congruent LiNbO3 suffers from a relatively low optical damage threshold that constitutes its major disadvantage for optoelectronic devices. The optical damage threshold is dependent on the amount of intrinsic defects and is considerably increased in stoichiometric material and in congruent material doped with specific impurities, such as Mg, In, Sc, and Zn. It has been recently shown that the doping with Hf leads to a significant increase of the photorefractive resistance at a threshold concentration of about 3 mol%. The study of the lattice location of Hf in LiNbO3 and its interaction with other impurities and intrinsic defects started more than a decade before the discovery of the role of this impurity, as Hf was a convenient probe for combined studies using the nuclear techniques perturbed angular correlations and Rutherford backscattering spectrometry/channeling. An integrated review of the main results obtained with these techniques is presented. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. [DOI: 10.1117/1.OE.53.6.060901

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Section: Factors Affecting the Lattice Location Of Hfmentioning

confidence: 99%

“…53 (6) 0.2 mol% HfO 2 , both ν Q ðLi IÞ and ν Q ðLi IIÞ were required for probes in Li sites. 76 Crystals codoped with 2 and 3 mol% HfO 2 plus 0.1 mol% Cr 2 O 3 were also studied using PAC. 78 The Hf probes were found occupying both Nb and Li sites in these crystals.…”

Section: Factors Affecting the Lattice Location Of Hfmentioning

confidence: 99%

Lattice location of Hf and its interaction with other impurities in LiNbO3: a review

Marques

Lorenz

2014

Opt. Eng

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“…Hf-doped crystals LN were grown with 1.0 mol% [49,192] and 6.0 mol% [138] of HfO2 in congruent melt. For comparison, samples of near-stoichiometric material, to which 4.6 wt % K2O was added, were doped with 0.2 and 1.0 mol% [138,193] HfO2. Although less popular as dopant for photorefractive suppression in LN, Hf is highly interesting for studies on the basic incorporation mechanism of dopants since it can be accessed simultaneously by RBS/C and PAC.…”

Section: Dopants To Increase Photorefractive Damage Resistancementioning

confidence: 99%

“…Hf-doped crystals LN were grown with 1.0 mol% [49,192] and 6.0 mol% [138] of HfO 2 in congruent melt. For comparison, samples of near-stoichiometric material, to which 4.6 wt % K 2 O was added, were doped with 0.2 and 1.0 mol% [138,193] RBS enabled to determine the actual concentrations of the melt grown samples and derive the corresponding distribution coefficients (Table 3). Channeling measurements for various axial direction proved that in the 1.0 mol% congruent crystal Hf occupies exclusively the Li site [49,192].…”

Section: Dopants To Increase Photorefractive Damage Resistancementioning

confidence: 99%

“…It can thus be safely assigned to Hf probes occupying Nb sites at room temperature. A frequency doublet for probes in Nb sites, ν Q1 = 353 MHz and ν Q2 = 494 MHz, was necessary for a good fit of the PAC spectra [193]. However, the best fits for the 6 mol% congruent and 0.2 mol% near stoichiometric crystals, for which the fraction of probes in Nb sites was close to 50%, were obtained without a fraction of probes in Li II sites.…”

Section: Dopants To Increase Photorefractive Damage Resistancementioning

confidence: 99%

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Unveiling the Defect Structure of Lithium Niobate with Nuclear Methods

Kling

Marques

2021

Crystals

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X-ray and neutron diffraction studies succeeded in the 1960s to determine the principal structural properties of congruent lithium niobate. However, the nature of the intrinsic defects related to the non-stoichiometry of this material remained an object of controversial discussion. In addition, the incorporation mechanism for dopants in the crystal lattice, showing a solubility range from about 0.1 mol% for rare earths to 9 mol% for some elements (e.g., Ti and Mg), stayed unresolved. Various different models for the formation of these defect structures were developed and required experimental verification. In this paper, we review the outstanding role of nuclear physics based methods in the process of unveiling the kind of intrinsic defects formed in congruent lithium niobate and the rules governing the incorporation of dopants. Complementary results in the isostructural compound lithium tantalate are reviewed for the case of the ferroelectric-paraelectric phase transition. We focus especially on the use of ion beam analysis under channeling conditions for the direct determination of dopant lattice sites and intrinsic defects and on Perturbed Angular Correlation measurements probing the local environment of dopants in the host lattice yielding independent and complementary information.

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