Preparation of YBa 2 Cu 3 O 7-δ Patterned Film Using Metal Organic Deposition with Electron Beam Irradiation

MgO has several advantageous characteristics and has been applied in various fields. In this study, we deposited Co nanoparticles in an island pattern on a Si substrate using an arc plasma gun (APG). We subsequently formed a MgO thin film on this substrate by metal–organic decomposition (MOD), which enables the formation of films in the atmosphere, thereby yielding a double-layer structure. The MgO thin film formed on Co nanoparticles deposited using the APG with 500 pulses of arc discharge exhibited improved crystallinity and photoelectron emission at least threefold higher than that of a MgO thin film formed directly without depositing Co nanoparticles. Although the transmittance of the specimen formed by depositing Co nanoparticles was initially 30% or lower, it increased to greater than 90% after the formation of the MgO thin film and the dispersion of the Co nanoparticles in the MgO thin film during heat treatment at 900 °C. Our results clarify that the characteristics of MgO thin films are markedly improved by depositing Co nanoparticles before forming the films. The results of Kelvin probe force microscopy (KPFM) indicate that the outermost surface of the Co material had become CoO (cobalt oxide) with the dispersion of Co nanoparticles in the MgO thin film. The lattice parameter of CoO nanoparticles (an-axis lattice parameter of 4.2615 Å) after heating matches well with that of MgO (4.2126 Å). The MgO thin films that grew in conjunction with the CoO nanoparticles were highly crystallized. We successfully established a high-performance, cost-effective bottom-up process that requires no ion injection by dispersing Co nanoparticles in a MgO thin film through heat treatment.

Section: Introductionmentioning

confidence: 99%

High photoelectron emission from Co-diffused MgO deposited using arc plasma gun

Yamamoto¹,

Kosuga²

2015

“…In addition, it has been reported that some precursor materials for MOD have electron-beam (EB) sensitivity. [1][2][3][4][5] The precursor films reacted with high-energy electrons and showed negative exposure characteristics. Some research groups fabricated functional metal-oxide micropatterns by an MOD method with EB irradiation using EB lithography (EBL) systems and succeeded in obtaining good physical properties.…”

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confidence: 99%

“…3) Tanabe et al fabricated YBa 2 Cu 3 O 7 micropatterns and succeeded in observing the superconductive transition. 4,5) This method can decrease drastically the number of fabrication steps for functional metal-oxide micropatterns, since only the EB-irradiation process is added to the conventional MOD method. Thus, this technique is very useful for forming micropatterns of various functional metal oxides using EBL systems, because it is difficult to etch functional metal oxides by a dry etching process.…”

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confidence: 99%

“…It is reported that the EB sensitivity of metal octylates is higher than that of naphthenates. 5) Figure 1 shows a schematic flow diagram of the fabrication process for YIG patterns prepared on GGG substrates by the MOD method with EB irradiation. Here, we used GGG substrates with a (111) orientation, which were already on the market (Saint-Gobain).…”

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confidence: 99%

“…This feature is similar to those of other metal octylates and naphthenates. [1][2][3][4][5]14) Okamura and Shiosaki reported that the EB sensitivity of the metal octylates for SrBi 2 TaO 9 was 1.9 × 10 3 µC=cm 2 , 14) and Tanabe et al reported that, for YBa 2 Cu 3 O 7 , it was 1.5 × 10 3 µC=cm 2 , 5) when the acceleration voltage was ∼30 kV. Thus, the EB dose required to expose our precursor materials is approximately one order of magnitude larger than that required to expose the metal octylates for SrBi 2 TaO 9 and YBa 2 Cu 3 O 7 .…”

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confidence: 99%

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Preparation of epitaxial yttrium–iron garnet micropatterns using metal–organic decomposition with electron-beam irradiation

Kasahara¹,

Manago²

2017

We have succeeded in obtaining epitaxial yttrium–iron garnet (YIG) micropatterns on a gadolinium-gallium garnet (GGG) substrate by a metal–organic decomposition method with electron-beam (EB) irradiation. We have demonstrated that metal-octylates of Y and Fe showed negative exposure behavior for EB irradiation. X-ray diffraction measurements indicated that the YIG micropatterns were epitaxially well grown on a GGG(111) substrate. The magnetization curve of the YIG micropatterns showed a clear hysteresis loop and the saturation magnetization was estimated to be approximately 100 emu/cm3, which is consistent with that of bulk YIG.

Magneto-optical images of submicron-size Bi-substituted YIG patterns prepared by electron-beam irradiated metal-organic decomposition

Kasahara

Wang

Ishibashi

et al. 2019

We investigated the magneto-optical properties of submicron-size epitaxial Bi-substituted yttrium-iron garnet (Bi:YIG) patterns fabricated by an electron-beam irradiated metal-organic decomposition (EB-MOD) method. The advantage of this method is that no dry etching process is required. The Bi:YIG pattern showed the clear magneto-optical Kerr effect (MOKE) hysteresis loop, and it was in good agreement with the magnetization curve of the Bi:YIG patterns. The MOKE image measurements revealed that the Bi:YIG pattern with a width of ∼0.71 μm prepared by the EB-MOD showed proper contrast changing behavior depending on magnetic fields, and it can maintain its MO property even in submicron-size.