Search results

1

Resonant Tunnelling in Double-Barrier Heterostructures with an Accumulation Layer

100%

Wosiński T., Figielski T., Mąkosa A., Wrotek S., Dobrowolski W.

Acta Physica Polonica A

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1998

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vol. 94

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issue 3

617-621

EN

Two modes of electron gas injection in resonant tunnelling through GaAs/AlGaAs double-barrier heterostructures were revealed while studying their current-voltage characteristics. Examining peculiarities of the characteristics within the temperature range 4-350 K and under a high magnetic field, we were able to distinguish the contribution to resonant tunnelling of ballistic electrons injected from a three-dimensional electron gas in the emitter contact and that of electrons injected from a two-dimensional electron gas in the accumulation layer formed near the emitter barrier.

2

Interlayer Exchange Coupling in Semiconductor EuS-PbS Ferromagnetic Wedge Multilayers

73%

Kowalczyk L., Wrotek S., Dziawa P., Osinniy V., Szot M., Story T., Sipatov A., Volobuev V., Fedorov A.

Acta Physica Polonica A

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2006

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vol. 110

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issue 2

225-231

EN

Antiferromagnetic interlayer coupling between ferromagnetic layers of EuS via nonmagnetic PbS spacer layer was experimentally studied in EuS-PbS wedge multilayers grown on KCl (001) substrates with EuS thickness of 6 nm and PbS thickness varying in the wedges in the range 0.3-6 nm (i.e. n=1-20 monolayers). Measurements of magnetic hysteresis loops of EuS-PbS multilayers performed in the temperature range 5-30 K by superconducting (SQUID) and magneto-optical magnetometers revealed a rapid increase in saturation magnetic field in multilayers with PbS spacer thinner than about 1.5 nm. It shows a monotonic increase in interlayer coupling strength with a decreasing PbS spacer thickness, in qualitative agreement with 1/2^n dependence predicted theoretically for semiconductor magnetic superlattices.

3

Vertical Electron Transport through PbS-EuS Structures

59%

Wrotek S., Dybko K., Morawski A., Mąkosa A., Wosiński T., Figielski T., Tkaczyk Z., Łusakowska E., Story T., Sipatov A., Szczerbakow A., Grasza K., Wróbel J., Palosz W.

Acta Physica Polonica A

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2003

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vol. 103

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issue 6

629-635

EN

Temperature dependence of current-voltage I-V characteristics and resistivity is studied in ferromagnetic PbS-EuS semiconductor tunnel structures grown on n-PbS (100) substrates. For the structures with a single (2-4 nm thick) ferromagnetic EuS electron barrier we observe strongly non-linear I-V characteristics with an effective tunneling barrier height of 0.3-0.7 eV. The experimentally observed non-monotonic temperature dependence of the (normal to the plane of the structure) electrical resistance of these structures is discussed in terms of the electron tunneling mechanism taking into account the temperature dependent shift of the band offsets at the EuS-PbS heterointerface as well as the exchange splitting of the electronic states at the bottom of the conduction band of EuS.

4

Fabrication and Electrical Characterization of PbS-EuS Ferromagnetic Semiconductor Microstructures

59%

Wrotek S., Morawski A., Tkaczyk Z., Mąkosa A., Wosiński T., Dybko K., Łusakowska E., Story T., Sipatov A., Péecz B., Grasza K., Szczerbakow A., Wróbel J.

Acta Physica Polonica A

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2004

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vol. 105

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issue 6

615-620

EN

Current-voltage characteristics and temperature dependence of differential conductance were studied in lithographically patterned (lateral dimensions from 10 x 10 μm^2 to 100 x 100 μm^2) ferromagnetic EuS-PbS-EuS microstructures. Below the ferromagnetic transition temperature a 4% decrease in the structure conductance was observed for mutual antiferromagnetic orientation of magnetization vectors of ferromagnetic EuS layers.

5

Magnetic and Structural Properties of EuS-PbS Multilayers Grown on n-PbS (100) Substrates

59%

Chernyshova M., Łusakowska E., Domukhovski V., Grasza K., Szczerbakow A., Wrotek S., Kowalczyk L., Story T., Smits C., Swagten H., De Jonge W., Palosz W., Sipatov A., Volobuev V.

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issue 4-5

609-615

EN

Magnetic properties of semiconductor EuS(t)-PbS(d)-EuS(t) ferromagnetic trilayers (t=30÷300Å and d=7.5÷70Å) grown on n-type monocrystalline PbS (100) substrate were studied by SQUID magnetometry and ferromagnetic resonance technique yielding, in particular, the dependence of the ferromagnetic Curie temperature on the thickness of the EuS layer. Structural parameters of layers were examined by X-ray powder diffraction analysis. A high structural quality of the substrate and the multilayer was verified by the measurements of the X-ray rocking curve width indicating the values of the order of 100 arcsec and by atomic force microscopy revealing the presence on the cleft PbS surface regions practically flat in the atomic scale over the area of 1×0.1μm^2.

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5 Acta Physica Polonica A

1 2006

1 2004

1 2003

1 2002

1 1998

5 Wrotek S.

4 Sipatov A.

4 Story T.

3 Grasza K.

3 Mąkosa A.

3 Szczerbakow A.

3 Wosiński T.

3 Łusakowska E.

2 Dybko K.

2 Figielski T.

2 Kowalczyk L.

2 Morawski A.

2 Palosz W.

2 Tkaczyk Z.

2 Volobuev V.

2 Wróbel J.

1 Chernyshova M.

1 De Jonge W.

1 Dobrowolski W.

1 Domukhovski V.

1 Dziawa P.

1 Fedorov A.

1 Osinniy V.

1 Péecz B.

1 Smits C.

1 Swagten H.

1 Szot M.

Resonant Tunnelling in Double-Barrier Heterostructures with an Accumulation Layer

Interlayer Exchange Coupling in Semiconductor EuS-PbS Ferromagnetic Wedge Multilayers

Vertical Electron Transport through PbS-EuS Structures

Fabrication and Electrical Characterization of PbS-EuS Ferromagnetic Semiconductor Microstructures

Magnetic and Structural Properties of EuS-PbS Multilayers Grown on n-PbS (100) Substrates