Journal Article

FZJ-2022-03670

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Growth and Oxygen Stoichiometry Control of High-Quality La 2 CoO 4+δ Single Crystals (δ = 0.25)

De Barros, R. ; Ceretti, M. (Corresponding author) ; Schmidt, W.FZJ* ; Pomjakushin, V. Y. ; Paulus, W.

2022
ACS Publ. Washington, DC

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Please use a persistent id in citations: http://hdl.handle.net/2128/32030  doi:10.1021/acs.cgd.2c00631

Abstract: La2CoO4+δ is a strongly correlated oxide with exciting physical and electronic properties originating from the subtle interplay of the lattice, orbital, charge, and spin degrees of freedom. In particular, oxygen-rich La2CoO4.25 is a key compound for studying oxygen and electronic ordering phenomena and their correlation. Single-crystal growth of these phases has been plagued by difficulties related to their incongruent melting. In this work, we report on the growth and characterization of high-quality, centimeter-sized La2CoO4.25 single crystals, suitable for neutron scattering experiments. La2CoO4+δ single crystals were grown by the traveling solvent floating zone without the addition of a solvent but continuously stabilizing the growth conditions. Postsynthesis annealing at 500 °C in oxygen flux yielded phase-pure La2CoO4.25, which was further characterized by single-crystal neutron and X-ray diffraction, as well as by scanning electron microscopy with energy-dispersive X-ray spectroscopy, revealing its quality in terms of composition, homogeneity, and crystalline quality. For La2CoO4.25, a complex structure with a two-dimensional modulation vector related to oxygen ordering was revealed by single-crystal X-ray and neutron powder diffraction studies. In addition, magnetic measurements coupled with preliminary single-crystal elastic neutron scattering experiments exhibited antiferromagnetic ordering with a Néel temperature (TN) of 36 K with a complex magnetic structure involving the doubling of all orthorhombic axes.

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Contributing Institute(s):

1. Streumethoden (JCNS-2)
2. Streumethoden (PGI-4)
3. JARA-FIT (JARA-FIT)
4. JCNS-ILL (JCNS-ILL)

Research Program(s):

1. 632 - Materials – Quantum, Complex and Functional Materials (POF4-632) (POF4-632)
2. 6G4 - Jülich Centre for Neutron Research (JCNS) (FZJ) (POF4-6G4) (POF4-6G4)

Experiment(s):

1. ILL-IN12: Cold neutron 3-axis spectrometer

Appears in the scientific report 2022

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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