Andrzej Morawski - Academia.edu (original) (raw)
Papers by Andrzej Morawski
Journal of Magnesium and Alloys, 2020
The effect of cold high pressure densification (CHPD) on anisotropy of the critical current densi... more The effect of cold high pressure densification (CHPD) on anisotropy of the critical current density (J c) in « in situ » single core binary and alloyed MgB 2 tapes has been determined as a function of temperatures at 4.2 K, 20 K and 25 K as well as at applied magnetic fields up to 19 T. The study includes binary and C 4 H 6 O 5 (malic acid) doped MgB 2 tapes before and after CHPD. It is remarkable that the CHPD process not only improved the J c values, in particular at the higher magnetic fields, but also decreased the anisotropy ratio, = J c // / J c ┴. In binary MgB 2 tapes, the anisotropy factor increases with higher aspect ratios, even after applying CHPD. In malic acid (C 4 H 6 O 5) doped tapes, however, the application of CHPD leads only to small enhancements of , even for higher aspect ratios. This is attributed to the higher carbon content in the MgB 2 filaments, which in turn is a consequence of the reduced chemical reaction path in the densified filaments. At all applied field values, it was found that CHPD processed C 4 H 6 O 5 doped tapes exhibit an almost isotropic behavior. This constitutes an advantage in view of industrial magnet applications using wires with square or slightly rectangular configuration.
IEEE Transactions on Applied Superconductivity, 2009
ABSTRACT
![Research paper thumbnail of [High pressure processing of spices in atmosphere of helium for decrease of microbiological contamination]](https://attachments.academia-assets.com/101581546/thumbnails/1.jpg)
](Roczniki Państwowego Zakładu Higieny, 2008
The aim of the study was to investigate the microbiological decontamination of coriander and cara... more The aim of the study was to investigate the microbiological decontamination of coriander and caraway when HPP technology was applied in elevated temperature in helium atmosphere. The HPP and heat treatment was conducted for 30 minutes at 800 and 1 000 MPa and temperature range was 60 - 121 degrees C. Contamination with aerobic mesophilic bacteria was decreased by about 2 logarithmic cycles. Total elimination of coliform and yeast and moulds was observed. The efficacy of HPP treatment under helium atmosphere depended on the content of the water in tested samples. It can be concluded that high pressure treatment under atmosphere of helium, combination of proper high pressure and time improved the microbiological quality of spices.
Acta Physica Polonica A, 1991
The effect of hydrostatic pressure on some properties of Cz-Si with oxygen precipitates is invest... more The effect of hydrostatic pressure on some properties of Cz-Si with oxygen precipitates is investigated. The observed phenomena are discussed in terms of misfit between the precipitates and Si matrix.
Physica C: Superconductivity, 1994
Abstract Single crystals of the HgBa 2 Ca n−1 Cu n O 2n+2+δ compounds have been grown using a hig... more Abstract Single crystals of the HgBa 2 Ca n−1 Cu n O 2n+2+δ compounds have been grown using a high gas pressure. The Hg1234 single crystals have a T c of 129 K. X-ray and TEM investigations proved the high quality of the crystal structure. Single crystals of the CaCuO 2 infinite layer compound of a size up to several mm 2 have been obtained under a high gas pressure without stabilizing additives of Sr or Li. The T c of the as grown crystals is 70–80 K
Journal of Superconductivity and Novel Magnetism, 2020
This article presents the impact of MgB2 wire bending and diameter on transport critical current ... more This article presents the impact of MgB2 wire bending and diameter on transport critical current density and irreversible magnetic field of a resultant coil. Unreacted MgB2 wires 500 mm in length and 0.63 or 0.83 mm in diameter have been used in the fabrication of small diameter (14 mm) superconducting coils. The coils were subsequently annealed under isostatic pressure of 1 GPa for 15 min at 700 °C and 725 °C. Our results indicate that larger wire diameter, higher annealing temperature, and bending lead to slight reduction of critical current density and irreversible magnetic field in the coil.
Journal of Superconductivity and Novel Magnetism, 2018
This article reports the influence of isostatic pressure (from 0.1 MPa to 1.1 GPa), low annealing... more This article reports the influence of isostatic pressure (from 0.1 MPa to 1.1 GPa), low annealing temperature of 570 • C, and annealing time for the formation of high-field pinning centers in 2% C-doped MgB 2 wires. Measurements indicate that 1.1 GPa pressure significantly increases the density of high-field pinning centers below 20 K. However, lower pressure (0.6 GPa) slightly increases the density of high-field pinning centers. Increasing the annealing time from 120 to 210 min leads to a reduction of critical temperature (T c), irreversibility field (B irr), critical current density (J c), and upper critical field (B c2), suggesting that a long annealing time leads to a reduction of high-field pinning center density and the number of connections between superconducting grains. The high pressures and low annealing temperature lead to a high critical current density of 1000 A/mm 2 in 7.2 T and 100 A/mm 2 in 12.5 T at 4.2 K in MgB 2 wires. Keywords Critical current density • High-field pinning centers • HIP process • MgB 2 wires • C doping
Journal of Alloys and Compounds, 2017
We report a study on the structural and transport properties of long in situ MgB 2 /Fe wires that... more We report a study on the structural and transport properties of long in situ MgB 2 /Fe wires that are prepared by use of amorphous boron and nano amorphous boron powders with 50e50% weight ratio. The wire samples are fabricated by means of a standard Powder-in-Tube (PIT) method. Transport measurements are applied under high magnetic fields, of up to 9 T, obtained in a Bitter magnet. We find that use of a mixture of the amorphous boron and amorphous nano boron precursor powders at equal amounts is very promising way to fabricate long wires without any degradation in transport engineering J ce values in the presence of low and moderate magnetic fields.
Journal of Applied Physics, 2016
High field pinning centers in MgB2 doped with 2 at. % carbon under a low and a high hot isostatic... more High field pinning centers in MgB2 doped with 2 at. % carbon under a low and a high hot isostatic pressures have been investigated by transport measurements. The field dependence of the transport critical current density was analyzed within the different pinning mechanisms: surface pinning, point pinning, and pinning due to spatial variation in the Ginzburg-Landau parameter (Δκ pinning). Research indicates that a pressure of 1 GPa allows similar pinning centers to Δκ pinning centers to be obtained. This pinning is very important, because it makes it possible to increase the critical current density in high magnetic fields at 20 K and 25 K. Our results indicate that the δT c and δl pinning mechanisms, which are due to a spatial variation in the critical temperature (T c) and the mean free path, l, respectively, create dislocations. The high density of dislocations with inhomogeneous distribution in the structure of the superconducting material creates the δl pinning mechanism. The low density of dislocations with inhomogeneous distribution creates the δT c pinning mechanism. Research indicates that the hot isostatic pressure process makes it possible to obtain a high dislocation density with a homogeneous distribution. This allows us to obtain the δT c pinning mechanism in MgB2 wires. In addition, a high pressure increases the crossover field from the single vortex to the small vortex bundle regime (B sb) and improves the δT c pinning mechanism. Our research has proved that a high pressure significantly increases the crossover field from the small bundle to the thermal regime (B th), with only a modest decrease in T c of 1.5 K, decreases the thermal fluctuations, increases the irreversibility magnetic field (B irr) and the upper critical field (B c2) in the temperature range from 4.2 K to 25 K, and reduces B irr and B c2 above 25 K.
Journal of Alloys and Compounds, 2021
Abstract The effects of heat treatment temperature, time and isostatic pressure on the grain conn... more Abstract The effects of heat treatment temperature, time and isostatic pressure on the grain connectivity and superconducting properties of Mg11B2 wires prepared using nano-amorphous isotopic boron powder (11B) have been investigated. The article presents detailed studies of the Mg11B2 material structure of the wires using scanning electron microscope (SEM). Heat treatment at low and high temperature for different annealing time and isostatic pressure does not create an internal macro-defect that disrupts connectivity in the Mg11B2 superconducting wires. Our study shows that dense longitudinal superconducting layers are formed at high annealing temperature of 800 °C for 60 min. Formation of dense longitudinal superconducting layers under high isostatic pressure (HIP) allow improved grain connectivity and high density of pinning centers and as a result, high engineering critical current density, Jec, at 4.2 K has been achieved. Also, high upper critical field (Bc2) and high irreversible magnetic field (Birr) were obtained using HIP process while superconducting transition temperature (Tc) was not significantly affected. Better grain connectivity obtained using high annealing temperature and long annealing time under low isotopic pressure leads to Jec enhancement at high magnetic fields at 20 K. Our results show that the annealing temperature of 800 °C for 60 min under isostatic pressure of 1 GPa yields the required Jec of 25 A/mm2 and 50 A/mm2 for ITER applications in magnetic fields of 8 T and 7 T, respectively. The promising results obtained in this work could pave the way for designing low activation superconducting Mg11B2 wires to be considered for next generation fusion magnets.
Superconductor Science and Technology, 2015
Multifilamentary MgB 2 wires were annealed under the high pressure of low-friction, solid state m... more Multifilamentary MgB 2 wires were annealed under the high pressure of low-friction, solid state media such as BN and graphite powders. The idea was to replace the hot isostatic pressing in argon medium, which is beneficial to wires transport properties but is difficult for application on an industrial scale. The experimental results show that annealing in BN or graphite under 200 MPa leads to enhancement of the critical current, similar to that observed earlier for high pressure argon annealing. An unwanted effect of the process is the flattening of the round wires, which after the treatment yields an elliptical cross section with b to a ratio of around 85 ± 5%. Comparison of critical currents and microstructure of samples synthesized with different parameters are presented.
Superconductor Science and Technology, 2013
ABSTRACT Unreacted MgB2 wires fabricated from SiC-doped precursor material by Hyper Tech Research... more ABSTRACT Unreacted MgB2 wires fabricated from SiC-doped precursor material by Hyper Tech Research, Inc. have been used to make small-diameter (14 mm) superconducting coils. All coils made of 500 mm length wires were subjected to hot isostatic pressure (HIP) treatment. The critical current density (Jc) parameters of coils were compared to straight samples characteristics. Both types of samples have been measured in perpendicular magnetic field configuration for Jc and pinning force density (Fp) evaluation. No significant Jc difference between the long wires on coils and straight wires was found. These results suggest that the critical current (Ic) for coils can be determined for straight samples (25 mm). SEM analysis indicated that a small diameter of the coil does not influence the structure of in situ MgB2 wire.
Superconductor Science and Technology, 2018
MgB 2 wire diameter reduction by hot isostatic pressing-a route for enhanced critical current den... more MgB 2 wire diameter reduction by hot isostatic pressing-a route for enhanced critical current density To cite this article: A Morawski et al 2018 Supercond. Sci. Technol. 31 075008 View the article online for updates and enhancements. Related content Hot isostatic pressing of multifilamentary MgB2 wires in solid state media for large scale application T Cetner, A Morawski, D Gajda et al.-Mechanism for high critical current density in in situ MgB2 wire with large areareduction ratio Motomune Kodama, Yota Ichiki, Kazuhide Tanaka et al.
Superconductor Science and Technology
Here we report a new versatile technique to manufacture MgB2 massive samples, called reverse adva... more Here we report a new versatile technique to manufacture MgB2 massive samples, called reverse advance internal magnesium diffusion (r-AIMI). The idea focuses on the goal of obtaining dense bulk or wire samples depending on synthesis conditions. In respect to the traditional AIMI procedure, in which a central Mg rod is covered with a B corona, here a Mg tube is filled with B powder and clad in a Ti external sheath, which is quite similar to the traditional (powder in tube) technique. After cold deformation, during which several intermediate low temperature heat treatments are necessary in order to relax the Ti sheath and Mg tube, samples are reacted at high temperature and ambient pressure to form a dense MgB2 core. The MgB2 phase results are totally disconnected from metallic sheath, and can be easily extracted and characterized. Critical current density measurements show values exceeding 106 A cm−2 below 1.5 T at 20 K. In the last part of the paper, we show the effect of final heat-...
Przegląd Elektrotechniczny, 2009
Superlattices and Microstructures, 1997
We have found a very promising way for obtaining thin and thick layers of the Hg-12(n-1)n homolog... more We have found a very promising way for obtaining thin and thick layers of the Hg-12(n-1)n homologous family (n=2,3,4) on various substrates, i.e., SrTiO 3 , LaAlO 3 , SrLaAlO 4 , and SrLaGaO 4 . Crystal growth of a thin layer from the melt is rapid (up to 15 microns/hour) and strongly depends on the p-T-x conditions. The substrate and the crucible materials exert strong influences on the purity of the layers. Pure superconducting phases can be grown on SrTiO 3 and LaAlO 3 substrates, while growing on the SrLaAlO 4 , and SrLaGaO 4 lead to chemical reactions and substrate decomposition. These effects are not observed for low temperature laser ablation. The orientation of the growing layer depends strongly on the initial substrate orientation. To obtain thin layers of mercury compounds, we have developed a special method which enables us to keep very high pressure vapour of mercury over the substrate during all processes. This is crucial to avoid mercury losses from pre-reacted thin la...
Journal of Alloys and Compounds, 2017
Journal of Magnesium and Alloys, 2020
The effect of cold high pressure densification (CHPD) on anisotropy of the critical current densi... more The effect of cold high pressure densification (CHPD) on anisotropy of the critical current density (J c) in « in situ » single core binary and alloyed MgB 2 tapes has been determined as a function of temperatures at 4.2 K, 20 K and 25 K as well as at applied magnetic fields up to 19 T. The study includes binary and C 4 H 6 O 5 (malic acid) doped MgB 2 tapes before and after CHPD. It is remarkable that the CHPD process not only improved the J c values, in particular at the higher magnetic fields, but also decreased the anisotropy ratio, = J c // / J c ┴. In binary MgB 2 tapes, the anisotropy factor increases with higher aspect ratios, even after applying CHPD. In malic acid (C 4 H 6 O 5) doped tapes, however, the application of CHPD leads only to small enhancements of , even for higher aspect ratios. This is attributed to the higher carbon content in the MgB 2 filaments, which in turn is a consequence of the reduced chemical reaction path in the densified filaments. At all applied field values, it was found that CHPD processed C 4 H 6 O 5 doped tapes exhibit an almost isotropic behavior. This constitutes an advantage in view of industrial magnet applications using wires with square or slightly rectangular configuration.
IEEE Transactions on Applied Superconductivity, 2009
ABSTRACT
Roczniki Państwowego Zakładu Higieny, 2008
The aim of the study was to investigate the microbiological decontamination of coriander and cara... more The aim of the study was to investigate the microbiological decontamination of coriander and caraway when HPP technology was applied in elevated temperature in helium atmosphere. The HPP and heat treatment was conducted for 30 minutes at 800 and 1 000 MPa and temperature range was 60 - 121 degrees C. Contamination with aerobic mesophilic bacteria was decreased by about 2 logarithmic cycles. Total elimination of coliform and yeast and moulds was observed. The efficacy of HPP treatment under helium atmosphere depended on the content of the water in tested samples. It can be concluded that high pressure treatment under atmosphere of helium, combination of proper high pressure and time improved the microbiological quality of spices.
Acta Physica Polonica A, 1991
The effect of hydrostatic pressure on some properties of Cz-Si with oxygen precipitates is invest... more The effect of hydrostatic pressure on some properties of Cz-Si with oxygen precipitates is investigated. The observed phenomena are discussed in terms of misfit between the precipitates and Si matrix.
Physica C: Superconductivity, 1994
Abstract Single crystals of the HgBa 2 Ca n−1 Cu n O 2n+2+δ compounds have been grown using a hig... more Abstract Single crystals of the HgBa 2 Ca n−1 Cu n O 2n+2+δ compounds have been grown using a high gas pressure. The Hg1234 single crystals have a T c of 129 K. X-ray and TEM investigations proved the high quality of the crystal structure. Single crystals of the CaCuO 2 infinite layer compound of a size up to several mm 2 have been obtained under a high gas pressure without stabilizing additives of Sr or Li. The T c of the as grown crystals is 70–80 K
Journal of Superconductivity and Novel Magnetism, 2020
This article presents the impact of MgB2 wire bending and diameter on transport critical current ... more This article presents the impact of MgB2 wire bending and diameter on transport critical current density and irreversible magnetic field of a resultant coil. Unreacted MgB2 wires 500 mm in length and 0.63 or 0.83 mm in diameter have been used in the fabrication of small diameter (14 mm) superconducting coils. The coils were subsequently annealed under isostatic pressure of 1 GPa for 15 min at 700 °C and 725 °C. Our results indicate that larger wire diameter, higher annealing temperature, and bending lead to slight reduction of critical current density and irreversible magnetic field in the coil.
Journal of Superconductivity and Novel Magnetism, 2018
This article reports the influence of isostatic pressure (from 0.1 MPa to 1.1 GPa), low annealing... more This article reports the influence of isostatic pressure (from 0.1 MPa to 1.1 GPa), low annealing temperature of 570 • C, and annealing time for the formation of high-field pinning centers in 2% C-doped MgB 2 wires. Measurements indicate that 1.1 GPa pressure significantly increases the density of high-field pinning centers below 20 K. However, lower pressure (0.6 GPa) slightly increases the density of high-field pinning centers. Increasing the annealing time from 120 to 210 min leads to a reduction of critical temperature (T c), irreversibility field (B irr), critical current density (J c), and upper critical field (B c2), suggesting that a long annealing time leads to a reduction of high-field pinning center density and the number of connections between superconducting grains. The high pressures and low annealing temperature lead to a high critical current density of 1000 A/mm 2 in 7.2 T and 100 A/mm 2 in 12.5 T at 4.2 K in MgB 2 wires. Keywords Critical current density • High-field pinning centers • HIP process • MgB 2 wires • C doping
Journal of Alloys and Compounds, 2017
We report a study on the structural and transport properties of long in situ MgB 2 /Fe wires that... more We report a study on the structural and transport properties of long in situ MgB 2 /Fe wires that are prepared by use of amorphous boron and nano amorphous boron powders with 50e50% weight ratio. The wire samples are fabricated by means of a standard Powder-in-Tube (PIT) method. Transport measurements are applied under high magnetic fields, of up to 9 T, obtained in a Bitter magnet. We find that use of a mixture of the amorphous boron and amorphous nano boron precursor powders at equal amounts is very promising way to fabricate long wires without any degradation in transport engineering J ce values in the presence of low and moderate magnetic fields.
Journal of Applied Physics, 2016
High field pinning centers in MgB2 doped with 2 at. % carbon under a low and a high hot isostatic... more High field pinning centers in MgB2 doped with 2 at. % carbon under a low and a high hot isostatic pressures have been investigated by transport measurements. The field dependence of the transport critical current density was analyzed within the different pinning mechanisms: surface pinning, point pinning, and pinning due to spatial variation in the Ginzburg-Landau parameter (Δκ pinning). Research indicates that a pressure of 1 GPa allows similar pinning centers to Δκ pinning centers to be obtained. This pinning is very important, because it makes it possible to increase the critical current density in high magnetic fields at 20 K and 25 K. Our results indicate that the δT c and δl pinning mechanisms, which are due to a spatial variation in the critical temperature (T c) and the mean free path, l, respectively, create dislocations. The high density of dislocations with inhomogeneous distribution in the structure of the superconducting material creates the δl pinning mechanism. The low density of dislocations with inhomogeneous distribution creates the δT c pinning mechanism. Research indicates that the hot isostatic pressure process makes it possible to obtain a high dislocation density with a homogeneous distribution. This allows us to obtain the δT c pinning mechanism in MgB2 wires. In addition, a high pressure increases the crossover field from the single vortex to the small vortex bundle regime (B sb) and improves the δT c pinning mechanism. Our research has proved that a high pressure significantly increases the crossover field from the small bundle to the thermal regime (B th), with only a modest decrease in T c of 1.5 K, decreases the thermal fluctuations, increases the irreversibility magnetic field (B irr) and the upper critical field (B c2) in the temperature range from 4.2 K to 25 K, and reduces B irr and B c2 above 25 K.
Journal of Alloys and Compounds, 2021
Abstract The effects of heat treatment temperature, time and isostatic pressure on the grain conn... more Abstract The effects of heat treatment temperature, time and isostatic pressure on the grain connectivity and superconducting properties of Mg11B2 wires prepared using nano-amorphous isotopic boron powder (11B) have been investigated. The article presents detailed studies of the Mg11B2 material structure of the wires using scanning electron microscope (SEM). Heat treatment at low and high temperature for different annealing time and isostatic pressure does not create an internal macro-defect that disrupts connectivity in the Mg11B2 superconducting wires. Our study shows that dense longitudinal superconducting layers are formed at high annealing temperature of 800 °C for 60 min. Formation of dense longitudinal superconducting layers under high isostatic pressure (HIP) allow improved grain connectivity and high density of pinning centers and as a result, high engineering critical current density, Jec, at 4.2 K has been achieved. Also, high upper critical field (Bc2) and high irreversible magnetic field (Birr) were obtained using HIP process while superconducting transition temperature (Tc) was not significantly affected. Better grain connectivity obtained using high annealing temperature and long annealing time under low isotopic pressure leads to Jec enhancement at high magnetic fields at 20 K. Our results show that the annealing temperature of 800 °C for 60 min under isostatic pressure of 1 GPa yields the required Jec of 25 A/mm2 and 50 A/mm2 for ITER applications in magnetic fields of 8 T and 7 T, respectively. The promising results obtained in this work could pave the way for designing low activation superconducting Mg11B2 wires to be considered for next generation fusion magnets.
Superconductor Science and Technology, 2015
Multifilamentary MgB 2 wires were annealed under the high pressure of low-friction, solid state m... more Multifilamentary MgB 2 wires were annealed under the high pressure of low-friction, solid state media such as BN and graphite powders. The idea was to replace the hot isostatic pressing in argon medium, which is beneficial to wires transport properties but is difficult for application on an industrial scale. The experimental results show that annealing in BN or graphite under 200 MPa leads to enhancement of the critical current, similar to that observed earlier for high pressure argon annealing. An unwanted effect of the process is the flattening of the round wires, which after the treatment yields an elliptical cross section with b to a ratio of around 85 ± 5%. Comparison of critical currents and microstructure of samples synthesized with different parameters are presented.
Superconductor Science and Technology, 2013
ABSTRACT Unreacted MgB2 wires fabricated from SiC-doped precursor material by Hyper Tech Research... more ABSTRACT Unreacted MgB2 wires fabricated from SiC-doped precursor material by Hyper Tech Research, Inc. have been used to make small-diameter (14 mm) superconducting coils. All coils made of 500 mm length wires were subjected to hot isostatic pressure (HIP) treatment. The critical current density (Jc) parameters of coils were compared to straight samples characteristics. Both types of samples have been measured in perpendicular magnetic field configuration for Jc and pinning force density (Fp) evaluation. No significant Jc difference between the long wires on coils and straight wires was found. These results suggest that the critical current (Ic) for coils can be determined for straight samples (25 mm). SEM analysis indicated that a small diameter of the coil does not influence the structure of in situ MgB2 wire.
Superconductor Science and Technology, 2018
MgB 2 wire diameter reduction by hot isostatic pressing-a route for enhanced critical current den... more MgB 2 wire diameter reduction by hot isostatic pressing-a route for enhanced critical current density To cite this article: A Morawski et al 2018 Supercond. Sci. Technol. 31 075008 View the article online for updates and enhancements. Related content Hot isostatic pressing of multifilamentary MgB2 wires in solid state media for large scale application T Cetner, A Morawski, D Gajda et al.-Mechanism for high critical current density in in situ MgB2 wire with large areareduction ratio Motomune Kodama, Yota Ichiki, Kazuhide Tanaka et al.
Superconductor Science and Technology
Here we report a new versatile technique to manufacture MgB2 massive samples, called reverse adva... more Here we report a new versatile technique to manufacture MgB2 massive samples, called reverse advance internal magnesium diffusion (r-AIMI). The idea focuses on the goal of obtaining dense bulk or wire samples depending on synthesis conditions. In respect to the traditional AIMI procedure, in which a central Mg rod is covered with a B corona, here a Mg tube is filled with B powder and clad in a Ti external sheath, which is quite similar to the traditional (powder in tube) technique. After cold deformation, during which several intermediate low temperature heat treatments are necessary in order to relax the Ti sheath and Mg tube, samples are reacted at high temperature and ambient pressure to form a dense MgB2 core. The MgB2 phase results are totally disconnected from metallic sheath, and can be easily extracted and characterized. Critical current density measurements show values exceeding 106 A cm−2 below 1.5 T at 20 K. In the last part of the paper, we show the effect of final heat-...
Przegląd Elektrotechniczny, 2009
Superlattices and Microstructures, 1997
We have found a very promising way for obtaining thin and thick layers of the Hg-12(n-1)n homolog... more We have found a very promising way for obtaining thin and thick layers of the Hg-12(n-1)n homologous family (n=2,3,4) on various substrates, i.e., SrTiO 3 , LaAlO 3 , SrLaAlO 4 , and SrLaGaO 4 . Crystal growth of a thin layer from the melt is rapid (up to 15 microns/hour) and strongly depends on the p-T-x conditions. The substrate and the crucible materials exert strong influences on the purity of the layers. Pure superconducting phases can be grown on SrTiO 3 and LaAlO 3 substrates, while growing on the SrLaAlO 4 , and SrLaGaO 4 lead to chemical reactions and substrate decomposition. These effects are not observed for low temperature laser ablation. The orientation of the growing layer depends strongly on the initial substrate orientation. To obtain thin layers of mercury compounds, we have developed a special method which enables us to keep very high pressure vapour of mercury over the substrate during all processes. This is crucial to avoid mercury losses from pre-reacted thin la...
Journal of Alloys and Compounds, 2017