Flexible ϵ-Fe2O3-Terephthalate Thin-Film Magnets through ALD/MLD

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2020-05-13

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Language

en

Pages

10

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ACS Applied Materials and Interfaces, Volume 12, issue 19, pp. 21912-21921

Abstract

Pliable and lightweight thin-film magnets performing at room temperature are indispensable ingredients of the next-generation flexible electronics. However, conventional inorganic magnets based on f-block metals are rigid and heavy, whereas the emerging organic/molecular magnets are inferior regarding their magnetic characteristics. Here we fuse the best features of the two worlds, by tailoring ϵ-Fe2O3-terephthalate superlattice thin films with inbuilt flexibility due to the thin organic layers intimately embedded within the ferrimagnetic ϵ-Fe2O3 matrix; these films are also sustainable as they do not contain rare heavy metals. The films are grown with sub-nanometer-scale accuracy from gaseous precursors using the atomic/molecular layer deposition (ALD/MLD) technique. Tensile tests confirm the expected increased flexibility with increasing organic content reaching a 3-fold decrease in critical bending radius (2.4 ± 0.3 mm) as compared to ϵ-Fe2O3 thin film (7.7 ± 0.3 mm). Most remarkably, these hybrid ϵ-Fe2O3-terephthalate films do not compromise the exceptional intrinsic magnetic characteristics of the ϵ-Fe2O3 phase, in particular the ultrahigh coercive force (∼2 kOe) even at room temperature.

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| openaire: EC/FP7/339478/EU//LAYERENG-HYBMAT

Keywords

atomic layer deposition, flexible magnet, molecular layer deposition, thin film, ϵ-FeO organic superlattice

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Citation

Philip, A, Niemelä, J P, Tewari, G C, Putz, B, Edwards, T E J, Itoh, M, Utke, I & Karppinen, M 2020, ' Flexible ϵ-Fe 2 O 3 -Terephthalate Thin-Film Magnets through ALD/MLD ', ACS Applied Materials and Interfaces, vol. 12, no. 19, pp. 21912-21921 . https://doi.org/10.1021/acsami.0c04665