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Comprehensive investigation of crystallographic, spin-electronic and magnetic structure of (Co₀.₂Cr₀.₂Fe₀.₂Mn₀.₂Ni₀.₂)₃O₄ : Unraveling the suppression of configuration entropy in high entropy oxides

Title data

Sarkar, Abhishek ; Eggert, Benedikt ; Witte, Ralf ; Lill, Johanna ; Velasco, Leonardo ; Wang, Qingsong ; Sonar, Janhavika ; Ollefs, Katharina ; Bhattacharya, Subramshu S. ; Brand, Richard A. ; Wende, Heiko ; de Groot, Frank M. F. ; Clemens, Oliver ; Hahn, Horst ; Kruk, Robert:
Comprehensive investigation of crystallographic, spin-electronic and magnetic structure of (Co₀.₂Cr₀.₂Fe₀.₂Mn₀.₂Ni₀.₂)₃O₄ : Unraveling the suppression of configuration entropy in high entropy oxides.
In: Acta Materialia. Vol. 226 (2022) . - No. 117581.
ISSN 1359-6454
DOI: https://doi.org/10.1016/j.actamat.2021.117581

Official URL: Volltext

Project information

Project title:
Project's official titleProject's id
Nachwuchsgruppe Lehrstuhl für Anorganische Aktivmaterialien electrochemischer Speicher Dr. Qingsong WangNo information

Abstract in another language

High entropy oxides (HEOs) are a rapidly emerging class of functional materials consisting of multiple principal cations. The original paradigm of HEOs assumes cationic occupations with the highest possible configurational entropy allowed by the composition and crystallographic structure. However, the fundamental question remains on the actual degree of configurational disorder in HEOs, especially, in systems with low enthalpy barriers for cation anti-site mixing. Considering the experimental limitations due to the presence of multiple principal cations in HEOs, here we utilize a robust and cross-referenced characterization approach using soft X-ray magnetic circular dichroism, hard X-ray absorption spectroscopy, Mössbauer spectroscopy, neutron powder diffraction and SQUID magnetometry to study the competition between crystal field stabilization energy and configurational entropy governing the cation occupation in a spinel HEO (S-HEO), (Co0.2Cr0.2Fe0.2Mn0.2Ni0.2)3O4. In contrast to the previous studies, the derived complete structural and spin-electronic model, (Co0.6Fe0.4)(Cr0.3Fe0.1Mn0.3Ni0.3)2O4, highlights a significant deviation from the hitherto assumed paradigm of entropy-driven non-preferential distribution of cations in HEOs. An immediate correlation of this result can be drawn with bulk as well as the local element specific magnetic properties, which are intrinsically dictated by cationic occupations in spinels. The real local lattice picture presented here provides an alternate viewpoint on ionic arrangement in HEOs, which is of fundamental interest for predicting and designing their structure-dependent functionalities.

Further data

Item Type: Article in a journal
Refereed: Yes
Keywords: High entropy spinel; Preferential cationic occupation; X-ray magnetic circular dichroism; Mössbauer spectroscopy; Neutron diffraction
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Lehrstuhl Anorganische Aktivmaterialien für elektrochemische Energiespeicher
Research Institutions > Research Centres > Bayerisches Zentrum für Batterietechnik - BayBatt
Result of work at the UBT: No
DDC Subjects: 500 Science > 500 Natural sciences
500 Science > 530 Physics
500 Science > 540 Chemistry
Date Deposited: 02 Nov 2022 08:59
Last Modified: 02 Nov 2022 08:59
URI: https://eref.uni-bayreuth.de/id/eprint/72590