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4 Acta Physica Polonica A

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Phase Structure and Heat Generation in the Co-Precipitated Magnetite Nanoparticles

100%

Pawlik P. , Pruba M. , Pawlik K. , Kotynia K.

Acta Physica Polonica A

2017

tom 131

nr 5

1217-1221

In the present studies the phase structure and magnetic ordering of magnetite nanoparticles were investigated. The powder samples were obtained by co-precipitation from Fe(III) and Fe(II) salts. SiO₂ coating was performed using the modified Stöber process. X-ray diffraction studies revealed presence of the only one Fe₃O₄ crystalline phase both for the non-coated and SiO₂-coated samples. The Mössbauer studies have shown differences in shapes of measured spectral lines for Fe₃O₄ particles subjected to the Stöber process and non-coated particles. The heating efficiency was measured for glycerol dispersed nanoparticles. The analysis have shown changes in specific loss power depending on the concentration of the nanoparticles and amplitude of alternating magnetic field.

Structural and Magnetic Studies of the Fe-Co-Zr-Mo-W-B Amorphous Alloy

88%

Kotynia K. , Pawlik P. , Hasiak M. , Pruba M. , Pawlik K.

Acta Physica Polonica A

2017

tom 131

nr 5

1204-1206

The paper presents a characterization of the phase structure by X-ray diffraction and isothermal magnetic entropy changes for the amorphous Fe₅₈Co₁₀Zr₁₀Mo₅W₂B₁₅ alloy sample in the as-quenched state. An ingot sample was obtained by arc-melting. The ribbon sample was obtained by the melt-spinning technique. The magnetic measurements at various temperatures allowed for the study of the Curie temperature T_{C} and magnetic entropy changes |ΔS_{M}|. In order to determine the Curie temperature T_{C} of amorphous phase, three independent methods were used. Determination of the Curie temperature T_{C} for the amorphous alloys is not a trivial problem, as magnetization does not decreases rapidly around T_{C}. Therefore it is essential issue to establish T_{C} using few complementary methods. X-ray diffraction analysis revealed a fully amorphous structure of the ribbon samples.

Effect of Tungsten Addition on Phase Constitution and Magnetic Properties of the Bulk Fe_{65}Pr_{9}B_{26-x}W_x Alloys

75%

Filipecka K. , Pawlik P. , Pawlik K. , Gębara P. , Przybył A. , Pruba M.

Acta Physica Polonica A

2015

tom 128

nr 1

104-106

The effect of tungsten addition on phase constitution and magnetic properties of the bulk Fe_{65}Pr_9B_{26-x}W_{x} (where x=2, 4, 6, 8) alloys was studied. The base alloys were prepared by arc-melting of the high purity elements under Ar atmosphere. Samples were produced by suction of an arc-molten alloy to a water-cooled copper mould (the suction-casting method). In order to develop nanocrystalline structure, the samples were subjected to annealing. Heat treatment resulted in an evolution of the phase constitution that caused changes in magnetic properties of the alloys. X-ray diffractometry was used to determine the phase composition of annealed samples. The analysis showed presence of hard magnetic Pr_2Fe_{14}B, paramagnetic Pr_{1+x}Fe_4B_4 and soft ferromagnetic α-Fe phases of annealed samples. The room temperature magnetic properties were determined from hysteresis loops measured by VSM magnetometer in the external magnetic field up to 2 T. The highest hard magnetic parameters were measured for the rod sample of Fe_{65}Pr_9B_{20}W_6 annealed at 1003 K for 5 min.

Iron Containing Supplement Biofer Investigated by X-ray Fluorescence, Energy Dispersive X-Ray Spectroscopy and Mössbauer Spectroscopy

75%

Brzozowski R. , Szałański P. , Kaźmierczak J. , Polański K. , Pruba M. , Moneta M.

Acta Physica Polonica A

2015

tom 128

nr 5

905-907

Iron, an important microelement essential to the functioning of the body, plays a special role in the process of respiration. There are more and more new products available on the pharmaceutical market. Some of them were the subject of previous studies, especially by using the Mössbauer spectroscopy. One of the latest is Biofer. For the present tests three tablets from three different production series of Biofer were used for examination of elemental composition using the X-ray fluorescence and energy dispersive X-ray spectroscopy methods. Information about oxidation of iron contained in the tablets was obtained with by means of the Mössbauer spectroscopy.