Neodymium sites in calcium lanthanide hexaaluminates, potential laser materials

Gbehi, T.; Théry, J.; Vivien, D.; Collongues, R.; Dhalenne, G.; Revcolevschi, A.

doi:10.1016/0022-4596(88)90242-3

Cited by 8 publications

(6 citation statements)

References 14 publications

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“…This assignment can be verified by EPR measurements, since quite different g-factors are expected if 7 (g ⊥ = 5g ), 9 (g ⊥ = 0) or 8 (g ∼ 4, g ⊥ ∼ 2) is the ground state [20]. The EPR spectra of Nd 3+ in hexa-aluminates at low x show at B c a single sharp line, while at B ⊥ c there is a nearly isotropic very broad line [3,4,21]. In the low-resolution spectra [21] a gradual shift and broadening of the lines as x increases has been observed.…”

Section: Polarization Spectramentioning

confidence: 83%

“…The EPR spectra of Nd 3+ in hexa-aluminates at low x show at B c a single sharp line, while at B ⊥ c there is a nearly isotropic very broad line [3,4,21]. In the low-resolution spectra [21] a gradual shift and broadening of the lines as x increases has been observed. The recent EPR data [22,23] for ASN: Nd (x = y = 0.01) reported g = 3.75 and g ⊥ = 1.76 and more complex behaviour at higher x.…”

Section: Polarization Spectramentioning

confidence: 92%

Section: The Models For Non-equivalent Nd 3+ Centres In Asn and Aslmentioning

confidence: 99%

“…Another argument for a unique centre model has been based on the EPR data [3,4,21]. The low-resolution EPR spectra of Nd 3+ in hexa-aluminates show at B c a single sharp line, while at B ⊥ c they show a nearly isotropic very broad one [3,4] and a gradual shift and broadening of the lines as x increases [21]. Recent EPR measurements [22,23] at 15 K on Sr 1−x Nd x Mg x Al 12−x O 19 (ASN) crystals with x 0.2 show that, if at low x the spectrum with the magnetic field parallel to the c-axis contains a single line, at larger Nd 3+ concentrations, several pairs of satellites placed almost symmetrically around this line were observed.…”

Section: The Models For Non-equivalent Nd 3+ Centres In Asn and Aslmentioning

confidence: 99%

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Disorder effects in Nd³⁺-doped strontium hexa-aluminate laser crystals

Lupeǐ¹,

Lupeǐ²,

Gheorghe³

et al. 2005

J. Phys.: Condens. Matter

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The high resolution and polarized absorption spectroscopic data of Nd 3+ -doped, Mg 2+ -compensated strontium hexa-aluminate Sr 1−x Nd y La x−y Mg x Al 12−x O 19 (ASL: Nd) crystals in an extended compositional range (0.01 x 0.5) are presented. This crystal offers for the Nd 3+ ions a unique crystallographic site (2d) with 12 O 2− coordination and ideal D 3h symmetry. The optical spectra in all this compositional range contain contributions from two families of structural centres, C 1 and C 2 (with two components C 2 and C 2 ), whose spectral features are mainly dependent on the composition parameter x. The presence of these centres is attributed to the cationic disorder. It is inferred that while the centres C 1 and C 2 are connected with the presence or absence of trivalent ions in the nearest (2d) coordination sphere normally occupied by Sr 2+ , the two components C 2 and C 2 are associated to the existence or lack of Mg 2+ ions in the nearest sphere of Al 3+ tetrahedral (Al 3+ tetr ) sites. This structural disorder leads to crystal-field perturbations by electric charge difference, although for C 1 centres the perturbation by ionic size differences is also evident. The polarized spectroscopy indicates departures from the selection rules for D 3h symmetry for C 1 centres, whereas both polarized spectra and crystal-field analysis confirm the near-D 3h symmetry for C 2 centres. The composition dependence of the spectra indicates that the distribution of the La 3+ and Nd 3+ ions at the (2d) sites is random, while that of the Mg 2+ in the Al 3+ tetr sites is correlated with the former. The connection of this structural model with the EPR data and with earlier models is discussed.

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Section: Polarization Spectramentioning

confidence: 83%

Section: Polarization Spectramentioning

confidence: 92%

Section: The Models For Non-equivalent Nd 3+ Centres In Asn and Aslmentioning

confidence: 99%

Section: The Models For Non-equivalent Nd 3+ Centres In Asn and Aslmentioning

confidence: 99%

See 2 more Smart Citations

Disorder effects in Nd³⁺-doped strontium hexa-aluminate laser crystals

Lupeǐ¹,

Lupeǐ²,

Gheorghe³

et al. 2005

J. Phys.: Condens. Matter

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“…Another optical application is lasing. , , − Pr 3+ and Tb 3+ are first-choice activators for visible solid-state lasers. Oxide crystals are the preferred host materials for reasons of thermal conductivity and mechanical strength.…”

Section: Lanthanum Hexaaluminate (Lha)mentioning

confidence: 99%

La-Doped Alumina, Lanthanum Aluminate, Lanthanum Hexaaluminate, and Related Compounds: A Review Covering Synthesis, Structure, and Practical Importance

Heveling

2023

Ind. Eng. Chem. Res.

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Advanced materials based on lanthanum–aluminum oxides are useful for many practical applications, not the least in catalysis, energy conversion and energy storage systems designed for a sustainable world economy. The three main La–Al–O (LAO) combinations of commercial interest are La-doped aluminas (LDA), lanthanum monoaluminate (LMA, a perovskite), and lanthanum hexaaluminate (LHA). Usually, the literature treats doped aluminas, perovskites, and hexaaluminates separately. The current review tries to identify common trends and features with respect to structure, synthesis, and applications of LAOs, which should lead to a more holistic understanding of their chemistry. This, in turn, should trigger innovative ideas with respect to new or improved applications. Apart from a variety of uses at low temperatures, the main advantages of LDA, LMA, LHA, and related compounds are their high-temperature stability and the extended applicability that comes with it.

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