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1

X-Ray High-Resolution Diffraction and Transmission Topography Study of InGaAs Grown by Liquid Encapsulated Czochralski Technique

100%

Kowalski G., Gronkowski J., Borowski J., Hruban A.

Acta Physica Polonica A

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2008

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vol. 114

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issue 2

391-398

EN

New results on ternary InGaAs crystals grown using liquid encapsulated Czochralski technique with constant liquid composition are reported. X-ray high-resolution diffractometry (rocking curves and reciprocal space maps) as well as X-ray topography using the transmission Lang setup were used. Growth history of the bulk ingots was revealed.

2

Superconductivity Study of GaN Highly Doped by Transition Metals

88%

Gosk J., Boćkowski M., Tokarczyk M., Kowalski G., Twardowski A.

Acta Physica Polonica A

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2013

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vol. 124

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issue 5

877-880

EN

GaN:Cr and GaN:Fe single crystals as well as GaN:Mn micropowders highly doped by transition metals were grown to investigate low temperature superconductivity. Magnetic measurements revealed type I superconductivity with T_{C} ≈ 6 K and H_{C} ≈ 600 Oe, identical for all compounds and also identical to that observed before in GaP:Cr and GaAs:Cr. The presence of amorphous inclusions of gallium may explain existing superconductivity as a result of a phase transition leading to β-Ga during cooling down of the sample. Since the observed parameters are close to those characteristic for superconducting Ga(II) this possibility could not be ruled out.

3

CVD Growth of Graphene Stacks on 4H-SiC (0001) Surface - X-ray Diffraction and Raman Spectroscopy Study

88%

Tokarczyk M., Kowalski G., Grodecki K., Urban J., Strupiński W.

Acta Physica Polonica A

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2013

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vol. 124

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issue 5

768-771

EN

Features associated with short and prolonged growth time in the chemical vapor deposition process of growth of graphene stacks on SiC (0001) substrate are reported. In particular general bimodal (as far as d_{002} interlayer spacing is concerned) distribution of graphene species across the surface of the samples is observed. It consists of thin few layer graphene coverage of most of the sample surface accompanied by thick graphite-like island distribution. It points to the two independent channels of graphene stacks growth with two characteristic growth rates.

4

Observation of Superconductivity in Highly Cr-Doped GaP Single Crystals

76%

Gosk J., Strzelecka G., Kowalski G., Hruban A., Kamińska M., Twardowski A., Gronkowski J.

Acta Physica Polonica A

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2006

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vol. 110

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issue 2

189-193

EN

Studying bulk GaP, highly doped with Cr, and searching for possible ferromagnetic semiconductor in view of spintronic applications, we found superconducting behavior of this material unexpectedly. Magnetization techniques and X-ray diffraction were applied to study these crystals. Magnetization revealed superconducting features up to about 6 K and X-ray studies showed that superconductivity might be related to small size Cr precipitates.

5

Observation of Magnetic Anisotropy in GaN:Cr Single Crystals

76%

Gosk J., Boćkowski M., Kowalski G., Grzegory I., Szczytko J., Twardowski A.

Acta Physica Polonica A

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2012

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vol. 122

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issue 6

1007-1009

EN

Magnetic properties of bulk wurtzite GaN:Cr single crystals were studied with the magnetic field applied parallel and perpendicular to the crystal wurtzite c-axis. Structure of the crystal was examined by the X-ray diffraction method. Strong anisotropy of magnetization at low temperatures (2-10 K) was observed. The experimental data suggest Cr to be in nonspherical d^4 configuration.

6

Structural and Electronic Properties of Graphene Oxide and Reduced Graphene Oxide Papers Prepared by High Pressure and High Temperature Treatment

64%

Tokarczyk M., Kowalski G., Witowski A., Koziński R., Librant K., Aksienionek M., Lipińska L., Ciepielewski P.

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vol. 126

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issue 5

1190-1194

EN

"Graphene paper" prepared by new proprietary method involving high pressure and high temperature treatment in the reduction process show new possibilities in this area. Different phase content: multilayer and single layer graphene stacks recorded in this study for RGO samples are accompanied by the specific electric and optical parameters. We have found that process temperatures above 900°C play crucial role in structural and other properties. For the process temperature around 2000°C we found the onset of the graphitization in the samples.

7

Magnetic Properties of Epitaxial Fe/(Ga,Mn)As Hybrids

52%

Kalbarczyk K., Dziatkowski K., Szczytko J., Gosk J., Tokarczyk M., Kowalski G., Twardowski A., Bednarski W., Ostrowski A., Waplak S., Martinek J., Liu X., Furdyna J.

Acta Physica Polonica A

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2013

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vol. 124

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issue 5

873-876

EN

Thin-film structures composed of two kinds of ferromagnetic material - metallic Fe and semiconducting (Ga,Mn)As - were investigated by means of SQUID magnetometry and ferromagnetic resonance spectroscopy. Dependence of remnant magnetic moment on temperature showed unexpected anisotropic features when recorded along two orthogonal in-plane directions. For one of these orientations, the change in sign of the slope of m(T) curve at the Curie point of (Ga,Mn)As was observed, while for the other, an analogous m(T) curve retained monotonic character. Based on the comparison with ferromagnetic resonance data, the apparent non-monotonicity was attributed to the temperature-induced change of balance between the external magnetic field and uniaxial magnetic anisotropy in the plane of Fe layer.

Refine search results

X-Ray High-Resolution Diffraction and Transmission Topography Study of InGaAs Grown by Liquid Encapsulated Czochralski Technique

Superconductivity Study of GaN Highly Doped by Transition Metals

CVD Growth of Graphene Stacks on 4H-SiC (0001) Surface - X-ray Diffraction and Raman Spectroscopy Study

Observation of Superconductivity in Highly Cr-Doped GaP Single Crystals

Observation of Magnetic Anisotropy in GaN:Cr Single Crystals

Structural and Electronic Properties of Graphene Oxide and Reduced Graphene Oxide Papers Prepared by High Pressure and High Temperature Treatment

Magnetic Properties of Epitaxial Fe/(Ga,Mn)As Hybrids