Composition depth profiles of superconducting MgB2 thin films determined by ion beam analysis methods

Great progress has been made in the deposition of MgB2 thin films since the discovery of superconductivity at 39 K in this two-band superconductor. In this review, deposition techniques used for MgB2 are described, with an emphasis on their meeting the critical requirements for growing high-quality MgB2 thin films. The availability of these thin films has contributed significantly to the research on the two-gap superconductivity in MgB2. MgB2 thin films have also been investigated for applications in high-field magnets, superconducting electronic devices and circuits, and radio-frequency cavities used in accelerators.

Section: Annealing Of B Films In Mg Vapormentioning

confidence: 99%

MgB₂thin films

2009

“…The appearance of the droplets was eliminated when the precursors were annealed in Ar instead of Mg vapour [5]. However, this approach requires a very precise balance of the processing parameters to get singlephase MgB 2 films because several competing processes take place simultaneously, which are the diffusion of B and Mg, sublimation of Mg and formation/decomposition of the MgB 2 phase depending on the local content of Mg. As the result, impurity phases, either metallic Mg or B-rich MgB 4 and MgB 6 compounds, appear and the homogeneity of the films is degraded [6,7]. In the present work we studied an intermediate approach for the annealing of multilayer B/Mg precursors in a flow of Mg vapour.…”

mentioning

confidence: 99%

Highly homogeneous MgB₂films prepared by a new post-annealing process

Matveev

Albrecht

Konuma

et al. 2005

Nanocrystalline MgB2 thin films were prepared on r-cut Al2O3 substrates by annealing of multilayer B/Mg precursors in a flow of Mg vapour. The films are highly homogeneous and show a smooth morphology at both the mesoscale and the microscale. The films exhibit a superconducting transition at Tc∼ 35 K with a transition width of ∼1.2 K and a critical current density at 10 K in the self-field of Jc∼1 × 107 A cm−2.

“…Precursor films or multilayers of MgB 2 , Mg + MgB 2 , or Mg + B, are deposited at room temperature to 300 • C, and then annealed in situ in the growth chamber at temperatures and duration such that severe Mg loss or MgB 2 decomposition does not occur. The precursor films may be deposited by pulsed laser deposition [10,35,38,53,54,57,55,56], sputtering [58][59][60], or thermal evaporation [47], or e-beam evaporation [61][62][63]. During the annealing, Mg sublimes or evaporates, MgB 2 phase forms, nucleation and growth of crystallites takes place, and MgB 2 decomposes.…”

Section: Intermediate-temperature Processesmentioning

confidence: 99%

Progress in the deposition of MgB₂thin films

Pogrebnyakov

Zeng

et al. 2004

An MgB 2 thin film deposition technology is the first critical step in the development of superconducting electronics utilizing the 39 K superconductor. It turned out to be a challenging task due to the volatility of Mg and phase stability of MgB 2 , the low sticking coefficients of Mg at elevated temperatures, and the reactivity of Mg with oxygen. A brief overview of current deposition techniques is provided here from a thermodynamic perspective, with an emphasis on a very successful technique for high quality in situ epitaxial MgB 2 films, the hybrid physical-chemical vapour deposition. Examples of heterostructures of MgB 2 with other materials are also presented.