MaTecK GmbH

Last Update
1st July 2007

Substrate single crystals & bicrystals for superconductivity

I. Substrate single crystals for superconductivity

Crystal	Structure	M.P. [°C]	Dielectric constant	Growth Technique	Info
Al₂O₃ Sapphire	Hexag. a=4.77Å c=13.04Å	2040	9.0/11.5 parallel/perpendicular C-axis	CZ
LaAlO₃	Rhombo a=3.790Å c=13.11Å	2100	24.5	CZ ø2"
Th: LaAlO₃	Cubic a=7.57Å	2080	24.0	CZ ø30mm
MgO	Cubic	2800	10	?
NdCaAlO₄	Tetrag. a=3.685Å c=12.12Å	1850	19.5	CZ ø30mm
NdGaO₃	Orthor. a=5.43Å b=5.50Å c=7.71Å	1600	25	CZ ø2"
SrLaAlO₄	Tetrag. a=3.756Å c=12.63Å	1650	16.8	CZ ø20mm
SrLaGaO₄	Tetrag. a=3.84Å c=12.68Å	1600	/	CZ ø20mm
SrTiO₃	Cubic a=3.90Å	2080	300	Verneuil ø20mm
YAlO₃	Orthog. a=5.176Å b=5.307Å c=7.355Å	1870	16`20	CZ ø30mm
YSZ	Cubic a=5.41Å	~2500	27	Flux

II. Substrate bicrystals for superconductivity

Material SrTiO₃ MgO Al₂O₃ YSZ Nb:SrTiO₃

Dimensions (mm) 10 x 10 x 0.5 10 x 10 x 0.5 10 x 10 x 0.5 10 x 10 x 0.5 10 x 10 x 0.5

Surface Orientation (100) ± 1° (100) ± 1° (1012) ± 1° (100) ± 1° (100) ± 1°

Surface Finish one side polished

Junction Angle 24° ± 1°
36.8° ± 1° 24° ± 1° 24° ± 1° 24° ± 1°
36.8° ± 1° 24° ± 1°
36.8° ± 1°

Flatness l/4 l/4 l/2 l/4 l/4

Surface Roughness Ra 10Å,
Rmax 30Å Ra 10Å,
Rmax 50Å Ra 10Å,
Rmax 50Å Ra 10Å,
Rmax 30Å Ra 10Å,
Rmax 30Å

Crystal Structure cubic cubic hexagonal cubic cubic

	a
Lattice Constant (Å)	b
	c

3.905

4.213

4.758

12.99

5.139

3.905

Phase Transition tetragonal
< 110K tetragonal
< 110K

Dielectric Constant (e) 310 10 9 27 310

Coefficient of Expansion (10^-6/°C) 11.1 14.2 7.5 10.3 11.1

Melting Point (°C) 2080 2800 2030 2500 2080

For other substrates and specifications please demand a quotation. The standard Nb doping amounts
of Nb:SrTiO₃ are 0.05 and 0.5 wt %. Surface roughness was measured using TALYSTEP (80µm width).