High-Quality Magnetically Hard ε-Fe2O3 Thin Films through Atomic Layer Deposition for Room-Temperature Applications
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2023-02
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en
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Advanced Engineering Materials, Volume 25, issue 2
Abstract
The critical-element-free ε-Fe2O3 ferrimagnet exhibits giant magnetic coercivity even at room temperature. It is thus highly attractive material for advanced applications in fields such as spintronics, high-density data storage, and wireless communication. However, a serious obstacle to overcome is the notoriously challenging synthesis of ε-Fe2O3 due to its metastable nature. Atomic layer deposition (ALD) is the state-of-the-art thin-film technology in microelectronics. Herein, it is demonstrated that it has also true potential for the fabrication of amazingly stable in situ crystalline and high-performance ε-Fe2O3 thin films from simple (FeCl3 and H2O) chemical precursors at a moderately low deposition temperature (280 °C). Standard X-ray diffraction and Fourier transfer infrared spectroscopy characterization indicates that the films are of high level of phase purity. Most importantly, precise temperature-dependent 57Fe Mössbauer spectroscopy measurements verify that the hematite (α-Fe2O3) trace in the films is below 2.5%, and reveal the characteristic low- and high-temperature transitions at 208–228 K and ≈480 K, respectively, while magnetization measurements confirm the symmetric hysteresis loops expected for essentially phase-pure ε-Fe2O3 films. Excitingly, the highly c-axis oriented film growth, the overall film quality, and the unique magnetic properties remain the same, independently of the substrate material used.Description
Publisher Copyright: © 2022 The Authors. Advanced Engineering Materials published by Wiley-VCH GmbH.
Keywords
ALD, atomic layer deposition, magnetic thin films, Mössbauer spectroscopy, thin films, ε-FeO
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Citation
Jussila, T, Philip, A, Lindén, J & Karppinen, M 2023, ' High-Quality Magnetically Hard ε-Fe 2 O 3 Thin Films through Atomic Layer Deposition for Room-Temperature Applications ', Advanced Engineering Materials, vol. 25, no. 2, 2201262 . https://doi.org/10.1002/adem.202201262