Abstract:Polycrystalline NiFe2O4 (NFO) thin films are grown on (111) platinized Si substrates via chemical solution processing. θ-2θ x-ray diffraction, x-ray pole figures and electron diffraction indicate that the NFO has a high degree of 〈111〉 uniaxial texture normal to the film plane. The texturing is initiated by nucleation of (111) planes at the Pt interface and is enhanced with decreasing film thickness. As the NFO magnetic easy-axis is 〈111〉, the out-of-plane magnetization exhibits improved Mr/Ms and coercivity w… Show more
“…This preferential orientation in the (111) direction could be induced by the Pt(111) substrates. The small lattice mismatch between CoFe 2 O 4 and Pt induced the nucleation of CFO grains with preferred (111) orientation on top of the (111)-oriented Pt substrate [21]. Figure 1
X-ray diffraction spectra.…”
We report the preparation of (111) preferentially oriented CoFe2O4 thin films on Pt(111)/TiO2/SiO2/Si substrates using a spin-coating process. The post-annealing conditions and film thickness were varied for cobalt ferrite (CFO) thin films, and Pt/CFO/Pt structures were prepared to investigate the resistance switching behaviors. Our results showed that resistance switching without a forming process is preferred to obtain less fluctuation in the set voltage, which can be regulated directly from the preparation conditions of the CFO thin films. Therefore, instead of thicker film, CFO thin films deposited by two times spin-coating with a thickness about 100 nm gave stable resistance switching with the most stable set voltage. Since the forming process and the large variation in set voltage have been considered as serious obstacles for the practical application of resistance switching for non-volatile memory devices, our results could provide meaningful insights in improving the performance of ferrite material-based resistance switching memory devices.
“…This preferential orientation in the (111) direction could be induced by the Pt(111) substrates. The small lattice mismatch between CoFe 2 O 4 and Pt induced the nucleation of CFO grains with preferred (111) orientation on top of the (111)-oriented Pt substrate [21]. Figure 1
X-ray diffraction spectra.…”
We report the preparation of (111) preferentially oriented CoFe2O4 thin films on Pt(111)/TiO2/SiO2/Si substrates using a spin-coating process. The post-annealing conditions and film thickness were varied for cobalt ferrite (CFO) thin films, and Pt/CFO/Pt structures were prepared to investigate the resistance switching behaviors. Our results showed that resistance switching without a forming process is preferred to obtain less fluctuation in the set voltage, which can be regulated directly from the preparation conditions of the CFO thin films. Therefore, instead of thicker film, CFO thin films deposited by two times spin-coating with a thickness about 100 nm gave stable resistance switching with the most stable set voltage. Since the forming process and the large variation in set voltage have been considered as serious obstacles for the practical application of resistance switching for non-volatile memory devices, our results could provide meaningful insights in improving the performance of ferrite material-based resistance switching memory devices.
“…This preferential orientation in the (111) direction could be induced by the Pt(111) substrates. The small lattice mismatch between CoFe 2 O 4 and Pt induced the nucleation of CFO grains with preferred (111) orientation on top of the (111)-oriented Pt substrate [21]. The RS properties of the Pt/CFO/Pt structures were directly affected by their initial resistance.…”
We report the preparation of (111) preferentially oriented CoFe 2 O 4 thin films on Pt(111)/TiO 2 /SiO 2 /Si substrates using a spin-coating process. The post-annealing conditions and film thickness were varied for cobalt ferrite (CFO) thin films, and Pt/CFO/Pt structures were prepared to investigate the resistance switching behaviors. Our results showed that resistance switching without a forming process is preferred to obtain less fluctuation in the set voltage, which can be regulated directly from the preparation conditions of the CFO thin films. Therefore, instead of thicker film, CFO thin films deposited by two times spin-coating with a thickness about 100 nm gave stable resistance switching with the most stable set voltage. Since the forming process and the large variation in set voltage have been considered as serious obstacles for the practical application of resistance switching for non-volatile memory devices, our results could provide meaningful insights in improving the performance of ferrite material-based resistance switching memory devices.
“…Most recently, we reported on uniaxially and biaxially textured NFO thin films deposited on (111) Pt and (0001) sapphire substrates, respectively . The textured films grown here by CSD are deposited and annealed at much lower temperature than previously reported epitaxial/textured NFO films by other techniques .…”
Section: Introductionmentioning
confidence: 89%
“…The 0.5 and 0.2 Molar (M) NFO precursor solutions are synthesized following a route based on 2‐methoxyethanol (CH 3 OCH 2 CH 2 OH) as solvent, described in detail previously . Nickel acetate tetrahydrate (Ni(CO 2 CH 3 ) 2 ·4H 2 O) and ferric nitrate nonahydrate (Fe(NO 3 ) 3 ·9H 2 O) are used as precursors (all supplied from Sigma Aldrich, Inc., St. Louis, MO).…”
Section: Methodsmentioning
confidence: 99%
“…Most recently, we reported on uniaxially and biaxially textured NFO thin films deposited on (111) Pt and (0001) sapphire substrates, respectively. 17,18 The textured films grown here by CSD are deposited and annealed at much lower temperature than previously reported epitaxial/textured NFO films by other techniques. 4,6,7 Here, we vary the processing parameters of biaxially textured NFO on c-plane sapphire to improve the degree of texture, achieve the epitaxial NFO thin films, and better understand the epitaxial relationship between the NFO films and sapphire substrates.…”
(111)-oriented epitaxial thin films of nickel ferrite (NFO) are grown on c-plane sapphire [a-Al 2 O 3 (0001)] substrates using a chemical solution deposition technique. The processing conditions, including pyrolysis and annealing temperatures, are varied to achieve a film that shows maximum texture and epitaxy. It is shown that increasing the pyrolysis temperature to 400°C and decreasing the annealing temperature to 750°C for 10 min result in the highest degree of texture in the films. Lower film thickness also leads to a higher degree of texture. Microstructural studies confirm an in-plane epitaxial relationship between the (111) NFO film and the (0001) Al 2 O 3 substrate in two variants, [110] NFO || ½10 10 Al2O3 or ½1 100 Al2O3 .
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