Crystal growth of Ln2NiO4 (Ln = La, Pr, Nd) by skull melting

Buttrey, Douglas J.; Harrison, H. R.; Honig, J.M.; Schartman, Richard

doi:10.1016/0022-4596(84)90172-5

Cited by 48 publications

(14 citation statements)

References 9 publications

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“…7a illustrates such a case: apart from the significantly worse agreement, the congruent transformation of La 2 NiO 4 is then replaced by a peritectic reaction. The congruent melting behavior of La 2 NiO 4 is strongly corroborated, however by the possibility to grow large and pure single crystals from the melt [22,74,75]. Nevertheless, the calculated liquidus, especially in the NiO-region is rather speculative.…”

Section: Resultsmentioning

confidence: 74%

Thermodynamic analysis of the ternary La–Ni–O system

Zinkevich

Aldinger

2004

Journal of Alloys and Compounds

117

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Section: Resultsmentioning

confidence: 74%

Thermodynamic analysis of the ternary La–Ni–O system

Zinkevich

Aldinger

2004

Journal of Alloys and Compounds

117

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“…The starting crystals with x = 0, 0.02, 0.04, 0.06, 0.08, and 0.12 were obtained by congruent melt growth using radio frequency induction skull melting. 35 To adjust δ, small crystal pieces were annealed at different temperatures in atmospheres with different oxygen fugacities f O2 ranging from log(f O2 ) = −12 to 0. Samples with low δ were obtained by anneals at 1000…”

Section: 3334mentioning

confidence: 99%

Oxygen and strontium codoping ofLa2NiO4: Room-temperature phase diagrams

et al. 2004

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We present a detailed room temperature x-ray powder diffraction study on La2−xSrxNiO 4+δ with 0 ≤ x ≤ 0.12 and 0 ≤ δ ≤ 0.13. For x = 0.02, 0.04 and 0.06 the oxygen content phase diagrams of the Sr-doped samples show a similar sequence of pure phases and miscibility gaps as for pure La2NiO 4+δ . We find a weak Sr doping dependence of the δ range for the pure LTO, LTT and HTT phases; but overall, the δ ranges of the different phases do not vary strongly for x ≤ 0.06. Drastic changes are observed for x = 0.08 and 0.12, where miscibility gaps successively disappear. For x = 0.12 all oxygen-doped samples are in the HTT phase. The mechanism responsible for the suppression of the phase separation seems to involves multiple factors, including the Coulomb interaction between Sr impurities and interstitial oxygens as well as the reduction of the NiO6 octahedral tilt angle. The doping dependence of the lattice parameters shows clear differences for pure Sr and pure O doping. With the exception of the LTO phase, the in-plane lattice parameters explicitly depend on the type of dopant, rather than the net hole content, p = x + 2δ. In contrast, the orthorhombic strain in the LTO phase as well as the c-axis length appears to depend only on p; however, in the case of the c-axis length this "universal" behavior turns out to be accidental. Our results also show that the chemical pressure of La-site dopants is highly anisotropic, whereas that of O interstitials appears to be more isotropic. In general, this study reveals that Sr-doped samples have to be annealed carefully to achieve δ = 0, and to permit the study of the intrinsic properties of La2−xSrxNiO4.

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“…The existence of crystals with ͳ values between 0 and 0.25 would justify the ͳ average value (0.14) found by mean of thermogravimetric measurements. (2) [010] o zone axis. Figure 5a shows the SAEDP along the [010] o zone axis, where satellite reflections due to a modulated structure along the a* o direction can be seen.…”

Section: Resultsmentioning

confidence: 99%

“…Since then, a considerable amount of work has indicated that superconductivity in this system is related directly to oxygen content. La 2 NiO 4ϩͳ exhibits a wide range of oxygen stoichiometry which has been attributed to the presence of intergrown phases or deviation in the metal-atom ratio (2).…”

Section: Introductionmentioning

confidence: 99%