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H-T Phase Diagram of Magnetic Semiconductor Thin Films - Experiment

100%

Lubecka M., Maksymowicz L. J., Szymczak R., Powroźnik W.

Acta Physica Polonica A

1997

vol. 92

issue 2

433-436

We used the irreversibilities between the field cooled and zero field cooled dc magnetization to determine the field and composition dependence of the spin-glass freezing temperature in CdCr_{2}Se_{4} : In (REE) and CdCr_{2-2x}In_{2x}Se_{4} (0.15 ≤ x ≤ 0.35) (SG) thin films. The H-T phase diagram of samples with REE has two instability lines: the Gabay-Toulouse-type (G-T) and the De Almeida-Thouless-type (A-T) while samples in SG state are characterized by the A-T line. The A-T line of thin films was used for calculation the normalised internal magnetic field h_{m} of infinite spin clusters with long range ordering.

Spin-Wave Resonance in Magnetic Semiconductor Thin Films - Experiment

100%

Maksymowicz L., Lubecka M., Powroźnik W.

Acta Physica Polonica A

1991

vol. 80

issue 5

653-664

Magnetic properties of polycrystalline thin films of chromium chalcogenide spinels (CdCr_{2}Se_{4} lightly doped with indium and CdCr_{2x}In_{2-2x}Se_{4}) were studied. The ferromagnetic (FMR) and spin-wave resonance (SWR) techniques were used to investigate the temperature dependences of both the spin-wave stiffness constant D and the saturation magnetization M_{s}. The resonance spectra were recorded in the temperature range extending from 4.2 K to 300 K. The influence of indium concentration on M_{s}(T) and D(T) was studied. It was shown that lightly doped samples (In/Cd < 1% at.) exhibited the ferromagnetic ordering with M_{s}(T) and D(T) being the linear functions of T^{3/2} and T^{5/2}, respectively. Higher concentration of indium produced the reentrant transition and spin-glass state of magnetic ordering in CdCr_{2x}In_{2-2x}Se_{4}. The temperature dependence of M_{s} was also found from the FMR data for these two magnetic phases.

Prototype Silicon Position-Sensitive Detector Working with Bragg-Brentano Powder Diffractometer

64%

Zięba A., Dąbrowski W., Gryboś P., Powroźnik W., Stobiecki T., Świentek K., Słowik J., Wiącek P.

Acta Physica Polonica A

2002

vol. 101

issue 5

629-634

A prototype 64-channel detector module, comprising a silicon strip detector with strip pitch of 100μm and 64-channel ASIC RX64, was tested with the X-Pert Philips MPD diffractometer. Basic parameters of the detector module, energy resolution, and detection efficiency, were evaluated as a function of the counting rate. Energy resolution of 1.1 keV FWHM for photon rate up to 1×10^7 photon/s per 1 cm of the active width of the detector was demonstrated. The prototype detector, when applied in a diffractometer utilizing Bragg-Brentano focusing principle, allows to increase the counting rate by about 2 orders of magnitude with respect to a single counter. Exemplary diffraction patterns of polycrystalline samples of Si and SiO_2 (quartz peak cluster) are presented.

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3 Acta Physica Polonica A

1 2002

1 1997

1 1991

3 Powroźnik W.

2 Lubecka M.

1 Dąbrowski W.

1 Gryboś P.

1 Maksymowicz L.

1 Maksymowicz L. J.

1 Stobiecki T.

1 Szymczak R.

1 Słowik J.

1 Wiącek P.

1 Zięba A.

1 Świentek K.

Search results

H-T Phase Diagram of Magnetic Semiconductor Thin Films - Experiment

Spin-Wave Resonance in Magnetic Semiconductor Thin Films - Experiment

Prototype Silicon Position-Sensitive Detector Working with Bragg-Brentano Powder Diffractometer