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Title: Growth of magnesium diboride films on 2 inch diameter copper discs by hybrid physical–chemical vapor deposition

Abstract

Magnesium diboride (MgB2) coating is a potential candidate to replace bulk niobium (Nb) for superconducting radio frequency cavities due to the appealing superconducting properties of MgB2. MgB2 coating on copper may allow cavity operation near 20–25 K as a result of the high transition temperature (T c) of MgB2 and excellent thermal conductivity of Cu. We have grown MgB2 films on 2 inch diameter Cu discs by hybrid physical–chemical vapor deposition for radio frequency characterization. Structural and elemental analyses showed a uniform MgB2 coating on top of a Mg–Cu alloy layer with occasional intrusion of Mg–Cu alloy regions. High T c values of around 37 K and high critical current density (J c) on the order of 107 A cm-2 at zero field were observed. Radio frequency measurements at 11.4 GHz confirmed a high T c and showed a quality factor (Q 0) much higher than for Cu and close to that of Nb.

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC); US Department of the Navy, Office of Naval Research (ONR)
OSTI Identifier:
1394779
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Superconductor Science and Technology; Journal Volume: 30; Journal Issue: 4
Country of Publication:
United States
Language:
English

Citation Formats

Withanage, Wenura K., Xi, X. X., Nassiri, Alireza, Lee, Namhoon, Wolak, Matthäus A., Tan, Teng, Welander, Paul B., Franzi, Matthew, Tantawi, Sami, and Kustom, Robert L.. Growth of magnesium diboride films on 2 inch diameter copper discs by hybrid physical–chemical vapor deposition. United States: N. p., 2017. Web. doi:10.1088/1361-6668/aa5999.
Withanage, Wenura K., Xi, X. X., Nassiri, Alireza, Lee, Namhoon, Wolak, Matthäus A., Tan, Teng, Welander, Paul B., Franzi, Matthew, Tantawi, Sami, & Kustom, Robert L.. Growth of magnesium diboride films on 2 inch diameter copper discs by hybrid physical–chemical vapor deposition. United States. doi:10.1088/1361-6668/aa5999.
Withanage, Wenura K., Xi, X. X., Nassiri, Alireza, Lee, Namhoon, Wolak, Matthäus A., Tan, Teng, Welander, Paul B., Franzi, Matthew, Tantawi, Sami, and Kustom, Robert L.. Thu . "Growth of magnesium diboride films on 2 inch diameter copper discs by hybrid physical–chemical vapor deposition". United States. doi:10.1088/1361-6668/aa5999.
@article{osti_1394779,
title = {Growth of magnesium diboride films on 2 inch diameter copper discs by hybrid physical–chemical vapor deposition},
author = {Withanage, Wenura K. and Xi, X. X. and Nassiri, Alireza and Lee, Namhoon and Wolak, Matthäus A. and Tan, Teng and Welander, Paul B. and Franzi, Matthew and Tantawi, Sami and Kustom, Robert L.},
abstractNote = {Magnesium diboride (MgB2) coating is a potential candidate to replace bulk niobium (Nb) for superconducting radio frequency cavities due to the appealing superconducting properties of MgB2. MgB2 coating on copper may allow cavity operation near 20–25 K as a result of the high transition temperature (T c) of MgB2 and excellent thermal conductivity of Cu. We have grown MgB2 films on 2 inch diameter Cu discs by hybrid physical–chemical vapor deposition for radio frequency characterization. Structural and elemental analyses showed a uniform MgB2 coating on top of a Mg–Cu alloy layer with occasional intrusion of Mg–Cu alloy regions. High T c values of around 37 K and high critical current density (J c) on the order of 107 A cm-2 at zero field were observed. Radio frequency measurements at 11.4 GHz confirmed a high T c and showed a quality factor (Q 0) much higher than for Cu and close to that of Nb.},
doi = {10.1088/1361-6668/aa5999},
journal = {Superconductor Science and Technology},
number = 4,
volume = 30,
place = {United States},
year = {Thu Feb 16 00:00:00 EST 2017},
month = {Thu Feb 16 00:00:00 EST 2017}
}
  • Here, magnesium diboride (MgB 2) coating is a potential candidate to replace bulk niobium (Nb) for superconducting radio frequency cavities due to the appealing superconducting properties of MgB 2. MgB 2 coating on copper may allow cavity operation near 20–25 K as a result of the high transition temperature (T c) of MgB 2 and excellent thermal conductivity of Cu. We have grown MgB 2 films on 2 inch diameter Cu discs by hybrid physical–chemical vapor deposition for radio frequency characterization. Structural and elemental analyses showed a uniform MgB 2 coating on top of a Mg–Cu alloy layer with occasionalmore » intrusion of Mg–Cu alloy regions. High T c values of around 37 K and high critical current density (J c) on the order of 107 A cm –2 at zero field were observed. Radio frequency measurements at 11.4 GHz confirmed a high T c and showed a quality factor (Q 0) much higher than for Cu and close to that of Nb.« less
  • Magnesium diboride (MgB 2) is considered a candidate for the next generation superconducting radio frequency (SRF) cavities due to its higher critical temperature T c (40 K) and increased superheating field (H sh) compared to other conventional superconductors. These properties can lead to reduced BCS surface resistance (R BCS S) and residual resistance (R res), according to theoretical studies, and enhanced accelerating field (E acc) values. Here, we investigated the possibility of coating the inner surface of a 3.9 GHz SRF cavity with MgB 2 by using a hybrid physical-vapor deposition (HPCVD) system designed for this purpose. To simulate themore » actual 3.9 GHz SRF cavity, we also employed a stainless steel mock cavity for the study. The film qualities were characterized on small substrates that were placed at the selected positions within the cavity. MgB 2 films on stainless steel foils, niobium pieces, and SiC substrates showed transition temperatures in the range of 30-38 K with a c-axis-oriented crystallinity observed for films grown on SiC substrates. Dielectric resonator measurements at 18 GHz resulted in a quality factor of over 30 000 for the MgB 2 film grown on a SiC substrate. Furthermore, by employing the HPCVD technique, a uniform film was achieved across the cavity interior, demonstrating the feasibility of HPCVD for MgB 2 coatings for SRF cavities.« less
  • The chemical vapor deposition (CVD) of copper from (hexafluoroacetylacetonate)(vinyltrimethylsilane)-copper(I) [Cu[sup I](hfac)(vtms)] and the thermal evaporation of copper on pyromellitic dianhydride-oxydianiline (PMDA-ODA) polyimide have been studied with a variety of techniques including reflection absorption infrared spectroscopy (RAIRS), ellipsometry, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Our studies reveal that the nucleation and growth of Cu by CVD occurs by the preferential reaction of surface carbonyl groups, (C=O)[sub a], of PMDA-ODA with the CVD reagent. Preferential trapping of thermally deposited metal atoms also has been seen, although the nucleation processes appear to be less chemically specificmore » than is seen in CVD growth on this substrate. Carbonyl groups at the surface of the polyimide react with the precursor molecules at 300 K, although the reactive sticking probabilities appear to be low ([much lt]10[sup [minus]3]). The facility of nucleation on the polyimide surface depends on both the number and orientation of the carbony groups on the polymer surface which, in turn, depends sensitively on the thickness of the film. The nucleation of Cu growth from Cu[sup I](hfac)(vtms) is found to proceed from surface reactions mediated by these surface groups. 63 refs., 19 figs., 2 tabs.« less
  • High {ital T}{sub {ital c}} superconducting Tl-Ba-Ca-Cu-O thin films have been prepared by a novel hybrid technique that combines electron beam evaporation with organometallic chemical vapor deposition (OMCVD). Multilayer thin films of Ba-Ca-Cu-O are prepared by sequential evaporation of BaF{sub 2}, CaF{sub 2}, and Cu sources onto single-crystal MgO (100) or yttria-stabilized zirconia substrates followed by annealing in a water vapor-saturated oxygen atmosphere. Thallium is then incorporated in these films in either of two ways: (1) OMCVD using thallium(cyclopentadienide) as the source or (2) vapor diffusion using bulk Tl-Ba-Ca-Cu-O superconductor as the source. The resultant films are single phase, consistingmore » predominantly of Tl{sub 1}Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub {ital x}} with crystallite Cu-O planes preferentially oriented parallel to the substrate surface. Resistivity measurements indicate superconducting onset temperatures above 120 K with zero resistance by 104 K. By eliminating the water vapor in the initial anneal, fluoride (originating from the Ba and Ca sources) may be retained in the film. Upon T1 incorporation, this promotes formation of the Tl{sub 1}Ba{sub 2}Ca{sub 1}Cu{sub 2}O{sub {ital x}} phase with preferential crystallite {ital c}-axis orientation perpendicular to the substrate surface.« less