Transmission Electron Microscopy and High-Resolution Electron Microscopy Study of YNi₂B₂C Thin Film on Y₂O₃-Buffered MgO

Abstract

An YNi 2 B 2 C thin film deposited on an Y 2 O 3 -buffered (001) MgO substrate by pulsed laser deposition has been investigated by X-ray diffraction, transmission electron microscopy (TEM), and high-resolution electron microscopy. Cross-sectional TEM analyses show that the YNi 2 B 2 C film grows in the [001] direction while the Y 2 O 3 buffer layer exhibits columnar growth in the [001] and [111] directions on the (001) MgO substrate, with the growth in the [001] direction being preferred. The orientation relationships of the YNi 2 B 2 C film, Y 2 O 3 buffer layer, and MgO substrate were obtained. The primary orientation relationship YNi, evident from X-ray analyses, was able to be confirmed in the TEM study. A hexagonal impurity phase Y 0.915 Ni 4.12 B with lattice parameters a ) 1.491 nm and c ) 0.692 nm was identified at the interface between the Y 2 O 3 buffer layer and the YNi 2 B 2 C thin film.

Microstructure and texture of YNi2B2C thin films grown on Ir buffered MgO(001)

“…Bright-field TEM micrographs and selected area diffraction patterns are shown in Fig. 9 EDX results also confirm that the Ir buffer completely diffuses into the borocarbide film. Figure 4͑a͒ is a cross-sectional TEM image of the YNi 2 B 2 C film grown on the Ir/ MgO substrate.…”

“…Figure 1 shows the resistance versus temperature measurements of three films deposited at different temperatures. The Y 0.915 Ni 4.12 B phase was previously reported by Cao et al 9 to precipitate at the interface. Figure 2 shows the x-ray diffraction patterns of an YNi 2 B 2 C film directly deposited onto MgO͑001͒, an Ir layer deposited directly onto MgO ͑001͒, and YNi 2 B 2 C films deposited onto Ir buffered MgO͑001͒ at the different deposition temperatures.…”

“…Haese et al 5 showed that films deposited by pulsed laser deposition ͑PLD͒ at room temperature were completely amorphous and, for substrate temperatures below 800°C, the YNi 2 B 2 C phase was not detectable in the films, neither for postannealed nor for in situ grown films. Transmission electron microscopy ͑TEM͒ shows that this oxide exists as a continuous interlayer between the MgO substrate and the YNi 2 B 2 C film, having a clear orientation relationship to both MgO and YNi 2 B 2 C. [8][9][10] Consequently, texturing of the YNi 2 B 2 C film occurs, which around 650 and 750°C grows a and c axis oriented, respectively. A steady increase in T c with increasing substrate temperature was observed as the formation of the YNi 2 B 2 C phase improved.…”

“…A steady increase in T c with increasing substrate temperature was observed as the formation of the YNi 2 B 2 C phase improved. [8][9][10][11] To prevent the formation of the oxide layer at the interface, it was the aim of this work to study YNi 2 B 2 C film growth on single crystal MgO ͑100͒ substrates with an Ir buffer layer. For PLD as well as for magnetron sputtering, X-ray diffraction ͑XRD͒ reveals the simultaneous formation of Y 2 O 3 ͑Refs.…”

Transmission Electron Microscopy and High-Resolution Electron Microscopy Investigation of the Microstructure of an YNi2B2C Thin Film

“…3,6 Most of the investigations into YNi 2 B 2 C thin films have focused on film preparation and characterization; however, microstructural investigations by transmission electron microscopy (TEM) are still limited. In a previous work, 7 The study provides an improved understanding of the growth processes of YNi 2 B 2 C thin films.…”