Effect of Ni Substitution on the Structural, Magnetic, and Electronic Structure Properties of Gd0.4Tb0.6(Co1−xNix)2 Compounds

Autor: Marcin Sikora, Anna Bajorek, Artur Chrobak, Józef Deniszczyk, Grzegorz Ziółkowski, Grażyna Chełkowska
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: International Journal of Molecular Sciences, Vol 23, Iss 21, p 13182 (2022)
Druh dokumentu: article
ISSN: 23211318
1422-0067
1661-6596
DOI: 10.3390/ijms232113182
Popis: The comprehensive research of magnetic and electronic structure properties of the new class of Gd0.4Tb0.6(Co1−xNix)2 compounds, crystallizing in the cubic Laves phase (C15), is reported. The magnetic study was completed with electrical resistivity and electronic structure investigations. The analysis of Arrott plots supplemented by a study of temperature dependency of Landau coefficients revealed that all compounds undergo a magnetic phase transition of the second type. Based on magnetic isotherms, magnetic entropy change (ΔSM) was determined for many values of the magnetic field change (μ0H), which varied from 0.1 to 7 T. For each compound, the ΔSM had a maximum around the Curie temperature. Both values of the |ΔSMmax| and relative cooling power RCP parameters increased with increasing nickel content. It is shown that structural disorder upon Co/Ni substitution influences some magnetic parameters. The magnetic moment values of Co atoms determined from different methods are quantitatively consistent. From the M(T) dependency, the exchange integrals JRR, JRT, and JTT between rare-earths (R) and transition metal (T) moments were evaluated within the mean-field theory (MFT) approach. The experimental study of the electronic structure performed with the use of the X-ray photoelectron spectroscopy (XPS) was completed by calculations using the full-potential linearized augmented plane waves (FP-LAPW) method based on the density functional theory (DFT). The calculations explained experimentally observed changes in the XPS valence band spectra upon the Ni/Co substitution.
Databáze: Directory of Open Access Journals
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