Projects per year
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.
Original language | English |
---|---|
Article number | 2201262 |
Journal | Advanced Engineering Materials |
Volume | 25 |
Issue number | 2 |
Early online date | 17 Nov 2022 |
DOIs | |
Publication status | Published - Feb 2023 |
MoE publication type | A1 Journal article-refereed |
Keywords
- ALD
- atomic layer deposition
- magnetic thin films
- Mössbauer spectroscopy
- thin films
- ε-FeO
Fingerprint
Dive into the research topics of 'High-Quality Magnetically Hard ε-Fe2O3 Thin Films through Atomic Layer Deposition for Room-Temperature Applications'. Together they form a unique fingerprint.Projects
- 1 Finished
-
PREIN: Photonics Research and Innovation
Mäkelä, K. (Principal investigator)
01/01/2019 → 31/12/2022
Project: Academy of Finland: Other research funding
Equipment
-
Raw Materials Research Infrastructure
Karppinen, M. (Manager)
School of Chemical EngineeringFacility/equipment: Facility