Influence of oxygen stoichiometry on Co3+ spin state transitions and magnetic properties in EuBaCo2O5+δ cobaltites

Kumari, A and Dhanasekhar, C and Adyam, V and Das, AK (2023) Influence of oxygen stoichiometry on Co3+ spin state transitions and magnetic properties in EuBaCo2O5+δ cobaltites. In: Journal of Magnetism and Magnetic Materials, 586 .

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Abstract

The layered EuBaCo2O5+δ (δ= 0.47) (EBCO) cobaltite shows various magnetic phases at high temperature and magnetic glassy state at low temperature. Further, the various magnetic phases of the EBCO are coupled with the spin state transition of Co3+ octahedra. In the present study, we report the structural and magnetization properties of the EBCO by changing the oxygen stoichiometry. The various oxygen compositions were obtained after post annealing the as-prepared EBCO cobaltite under argon and oxygen atmospheres and the final stoichiometry was detected from the iodometric titrations. The δ= 0.13 and 0.67 samples show the tetragonal symmetry (space group, P4/mmm), whereas the δ= 0.41, 0.47 and 0.58 samples show the orthorhombic symmetry (space group, Pmmm). The magnetization measurements on the δ= 0.13 sample shows the paramagnetic to antiferromagnetic ordering at TN= 288 K and the electrical resistivity analysis shows the Co2+ and Co3+ charge ordering at TCO= 180 K. Further, the δ= 0.13 sample show the absence of the ferromagnetic phase and Co3+ spin state transitions. The δ= 0.58 and 0.67 samples show the coexistence of ferromagnetic and antiferromagnetic phases, however, the features of Co3+ intermediate spin (IS) to low spin (LS) state transition is suppressed, which is observed in δ= 0.47 sample at 151 K. Our results indicate a tuning of the crystal structure along with the magnetic properties and also the Co3+ spin state transitions by oxygen stoichiometry variation in EuBaCo2O5+δ cobaltites. © 2023 Elsevier B.V.

Item Type:	Journal Article
Publication:	Journal of Magnetism and Magnetic Materials
Publisher:	Elsevier B.V.
Additional Information:	The copyright for this article belongs to the Elsevier B.V.
Keywords:	Annealing; Antiferromagnetism; Cobalt compounds; Crystal structure; Europium compounds; Ferromagnetic materials; Ferromagnetism; Glass; Magnetic properties; Magnetization; Oxygen; Phase separation; Spin dynamics; Spin glass; Stoichiometry; Temperature, Co3� spin state transition; Ferromagnetic phasis; Glassy state; Layered cobaltites; Magnetic glassy state; Magnetic phase; Magnetic phase separation; Oxygen stoichiometry; Space Groups; Spin state transition, Barium compounds
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	10 Nov 2023 09:58
Last Modified:	10 Nov 2023 09:58
URI:	https://eprints.iisc.ac.in/id/eprint/83184

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