Nanostructure-driven complex magnetic behavior of Sm2CoMnO6 double perovskite

•Study of Sm2CoMnO6, a prototypical multifunctional magnetic double perovskite.•Presence of ferro- and antiferromagnetic phases, but no evidence of exchange bias.•Micromagnetic model shows complex nanostructure, explaining the experimental result.•Nanostructure with ferromagnetic clusters and antife...

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Veröffentlicht in:Journal of alloys and compounds 2022-06, Vol.906, p.164385, Article 164385
Hauptverfasser: Muscas, Giuseppe, Prabahar, K., Congiu, Francesco, Datt, Gopal, Sarkar, Tapati
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Sprache:eng
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Zusammenfassung:•Study of Sm2CoMnO6, a prototypical multifunctional magnetic double perovskite.•Presence of ferro- and antiferromagnetic phases, but no evidence of exchange bias.•Micromagnetic model shows complex nanostructure, explaining the experimental result.•Nanostructure with ferromagnetic clusters and antiferromagnetic antisite defects.•Random uncorrelated antiferromagnetic point-like defects do not cause exchange bias. [Display omitted] Magnetic double perovskite oxides have steadily emerged as an important class of functional materials. A clear understanding of the complex interactions that govern the magnetic behavior, and thereby, the functionality in these mixed valence compounds, however, remains elusive. In this study, we show that the complex nanostructure that forms in these compounds is at the root of their magnetic behavior. Using complementary experimental and micromagnetic simulation results, we have uncovered the complex nanostructure of polycrystalline Sm2CoMnO6, a typical double perovskite oxide, and established how the nanostructure drives its magnetic behavior. Our results show that Sm2CoMnO6 exhibits a Griffiths phase with the formation of ferromagnetic clusters above the ordering temperature. The isothermal magnetization curves show no sign of saturation, even at the highest measured field (9 T), and irreversibility in the entire magnetic field range. Despite a very clear indication of the presence of antiferromagnetic antisite defects, surprisingly, no antisite defect-induced exchange bias occurs. This is explained from the micromagnetic simulations that confirm the presence of ferromagnetic nanoclusters and nanosized, random, and uncorrelated antisite defects, resulting in no exchange bias. This work provides a clear understanding of the role of antisite defects, in particular, on how their structure can lead to the presence/absence of exchange bias. The fundamental insight offered in this work fills an important knowledge gap in the field and will be of immense value in realizing the true potential of double perovskite oxides for future technological applications.
ISSN:0925-8388
1873-4669
1873-4669
DOI:10.1016/j.jallcom.2022.164385