1887
banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
Suppression of superconductivity in epitaxial MgB2 ultrathin films
Rent:
Rent this article for
USD
10.1063/1.4812738
/content/aip/journal/jap/114/2/10.1063/1.4812738
http://aip.metastore.ingenta.com/content/aip/journal/jap/114/2/10.1063/1.4812738

Figures

Image of FIG. 1.
FIG. 1.

Temperature dependence of the resistivity for MgB films prepared by HPCVD method with thicknesses ranging from 35 nm to 6 nm (solid lines). Note that the vertical axis is in logarithmic scale. The dashed lines are fits to Eq. (1) according to the Bloch-Grüneisen formula with parameters listed in Table I .

Image of FIG. 2.
FIG. 2.

Thickness dependence of the rescaled residual resistivity (circles). The has been estimated from the values of shown in Table I by using Rowell's approach. For comparison, the data reported previously by Wang (squares, Ref. ), Zhang (diamonds, Ref. ), and Zhuang (triangles, Ref. ) for MgB films fabricated by the HPCVD method have been rescaled in the same way and included in the figure.

Image of FIG. 3.
FIG. 3.

Thickness dependence of the scattering rates deduced from the resistivity data for MgB films prepared by HPCVD (in the present work and in Refs. ). The Γ denotes the parallel between the intraband scattering rates and and is calculated from the rescaled as shown in Fig. 2 . The is the interband scattering rate estimated from the suppression of the superconducting critical temperature through Eq. (2) .

Image of FIG. 4.
FIG. 4.

(a) Temperature dependence of the rescaled resistivity, , in the vicinity of the superconducting transition for MgB films. (b) Thickness dependence of the superconducting critical temperature for MgB films towards the ultrathin limit (circles). The is determined as the midpoint of the superconducting transition as shown in (a). Also shown is the of the MgB films prepared by the HPCVD method in previous works of Wang (squares, Ref. ), Zhang (diamonds, Ref. ), and Zhuang (triangles, Ref. ). Shaded area is a guide to the eye.

Image of FIG. 5.
FIG. 5.

Comparison of the for MgB films towards the ultrathin limit among experimental reports and theoretical calculations. Solid symbols show the thickness dependence of the for MgB films prepared by three different methods: HPCVD (circles, present work and Refs. ), co-evaporation by Shimakage (squares, Ref. ), and MBE by Shibata (diamonds, Ref. ). The in squares is determined by averaging the onset and zero-resistance critical temperatures quoted from Ref. , with error bars representing the transition width. The in diamonds is quoted from Ref. as the midpoint of the superconducting transition. The dashed line illustrates the theoretical calculations by Szałowski within a multiband BCS model. The dotted lines through the experimental data points are fits to Eq. (4) according to the model of proximity effect. The fitting parameters are shown in Table II .

Image of FIG. 6.
FIG. 6.

(a) Residual resistivity dependence of the for MgB films towards the ultrathin limit prepared by HPCVD (circles, present work and Refs. ), co-evaporation (squares, Ref. ), and MBE (diamonds, Ref. ). The in squares and diamonds are quoted as the normal-state resistivity at 40 K from Refs. , respectively. Inset shows the same data as the main panel with on a log scale. (b) Sheet resistance ( ) dependence of the for MgB films as shown in (a). Inset shows the data with on a log scale.

Image of FIG. 7.
FIG. 7.

Plot of ln as a function of 1/ for ultrathin MgB films prepared by three different methods. The data are the same as displayed in Fig. 5 . The roughly linear decrease of ln with increasing 1/ indicates , as expected from the model of proximity effect. Dotted lines are fits to Eq. (4) with parameters listed in Table II . The same fits have been shown in Fig. 5 as well.

Tables

Generic image for table
Table I.

Parameters , , and obtained by fitting the resistivity of MgB films (45–300 K) to Eq. (1) .

Generic image for table
Table II.

Fits of the for MgB films to Eq. (4) . Three sets of the data correspond to the films grown by three different methods: HPCVD (present work and Refs. ), co-evaporation, and MBE. The fits are demonstrated in Fig. 5 and Fig. 7 by dotted lines.

Loading

Article metrics loading...

/content/aip/journal/jap/114/2/10.1063/1.4812738
2013-07-08
2014-04-24
Loading

Full text loading...

This is a required field
Please enter a valid email address
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: Suppression of superconductivity in epitaxial MgB2 ultrathin films
http://aip.metastore.ingenta.com/content/aip/journal/jap/114/2/10.1063/1.4812738
10.1063/1.4812738
SEARCH_EXPAND_ITEM