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1

NMR (^{55}Mn, ^{139}La) and Mössbauer Spectroscopy (^{119}Sn) Studies of (La_{0.67}Ca_{0.33})(Mn_{1-x}Sn_x)O_{3-δ} Compounds

100%

Przewoźnik J.

Acta Physica Polonica A

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2007

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vol. 111

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issue 5

649-659

EN

A ^{119}Sn Mössbauer spectroscopy and zero field ^{55}Mn and ^{139}La NMR studies of (La_{0.67}Ca_{0.33})(Mn_{1-x}Sn_x)O_{3-δ} (x=0, 0.01, 0.03, andδ≈0.06) were reported. The temperature evolution of the Sn hyperfine field (B_{hf}) for x=0.03 determined from the Mössbauer spectroscopy measurements was analysed within a molecular field model. A fit to the temperature dependence of B_{hf}^{max} provided the Curie temperature T^*_C=160(3) K, which is in good agreement with T_C obtained from dc magnetisation measurements. The ^{55}Mn NMR spectra for $x=0$ and 0.01 show a single double exchange Mn^{3+/4+} resonance line and exhibit strong Suhl-Nakamura relaxation effects characteristic of the ferromagnetic metallic phase. The spectra for x=0.03 show a coexistence of the double exchange line with the lines characteristic of Mn^{3+} and Mn^{4+} valence states. This shows that a 3% Sn doping strongly suppresses the double exchange interaction and leads to microscopic phase segregation into ferromagnetic metal and ferromagnetic insulator.

2

Magnetism and Specific Heat of TmRhX (X = Ga, Ge) Compounds

51%

Baran S., Przewoźnik J., Szytuła A.

Acta Physica Polonica A

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2013

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vol. 124

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issue 6

998-1001

EN

Magnetic and specific heat data of the TmRhX (X = Ga, Ge) compounds are reported. These compounds crystallize in an orthorhombic crystal structure of the TiNiSi-type (space group Pnma). Magnetic data indicate that the compounds are antiferromagnets with the Néel temperature T_{N} equal to 3.9 K for TmRhGa and 6.0 K for TmRhGe. Magnetic susceptibility of TmRhGe has an additional peak at T_{t} = 10.6 K. In TmRhGe temperature dependence of χ"(T), the positions of both the peaks at T_{N} and T_{t} change with frequency indicating a relaxation process. These data suggest that with the decreasing temperature, first a cluster glass state and next the long-range aniferromagnetic order exists.

3

High-Pressure Mössbauer Studies of Magnetism in ScFe_2 and Sc_{0.4}Ti_{0.6}Fe_2 Laves Phases

45%

Rupprecht K., Lu J., Wortmann G., Przewoźnik J., Żukrowski J.

Acta Physica Polonica A

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2001

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vol. 100

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issue 5

789-797

EN

We report on ^{57}Fe-Mössbauer studies of the magnetic properties in ScFe_2 and Sc_{0.4}Ti_{0.6}Fe_2 performed as a function of pressure and temperature. Both systems crystallize in the C14-type Laves phase structure with two different Fe sites 6h and 2a. The ferromagnetic properties of ScFe_2 (T_C=540 K at ambient pressure) change around 30 GPa to antiferromagnetic order of the 6h sites with non-magnetic 2a sites. The ordering temperature is lowered to T_N=300 K at 51 GPa. This pressure-dependent behaviour of ScFe_2 resembles that observed within the Sc_{1-x}Ti_xFe_2 series as a function of x. In ferromagnetic Sc_{0.4}Ti_{0.6}Fe_2 we observe, as a function of temperature and of pressure, an abrupt high-moment to low-moment transition of the Fe band moments of the 6h sites, accompanied by a rearrangement of the spin directions. In both systems the decrease in the Fe moments is accompanied by a strong increase in the volume coefficient of the isomer shift, originating from a reduced s-electron shielding capability of the d-electrons in the low-moment state.

4

Magnetic Properties of Dy_{11}Si_4In_6

39%

Duraj D., Baran S., Jaworska-Gołąb T., Kalychak Y., Przewoźnik J., Szytuła A., Tyvanchuk Y.

Acta Physica Polonica A

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2012

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vol. 121

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issue 5-6

1118-1120

EN

Magnetic and specific heat measurements of Dy_{11}Si_4In_6 are reported. This compound crystallizes in the tetragonal Sm_{11}Ge_4In_6-type crystal structure (space group I4/mmm), in which Dy atoms occupy four different sites. The AC and DC magnetic measurements suggest complex magnetic properties. Below T_{c} = 52 K magnetic ordering has a ferromagnetic component, while below 20 K a change of the properties is observed. Near the Curie temperature the magnetocaloric effect with the magnetic entropy change ΔS_{m} equal to 16.5 J/(kg K) is observed. The specific heat data indicate only the phase transition at 52 K.

5

Magnetization, Susceptibility and Critical Currents of (Tl_{2-x}Re_{x})Ba_{2}CaCu_{2}O_{y} Thin Films

39%

Woch W., Dujavová A., Przewoźnik J., Zalecki R., Kołodziejczyk A., Sojková M., Chromik Š.

Acta Physica Polonica A

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2012

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vol. 121

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issue 4

845-849

EN

The magnetization and the AC susceptibility vs. the temperature as well as the applied magnetic field of the thin film (Tl_{2-x}Re_{x})Ba_{2}CaCu_{2}O_{y} with x=0 and 0.15 on R-plane sapphire substrate with CeO_{2} buffer layer were measured and analyzed. XRD measurements show c-axis as well as a-b plane oriented Tl-1212 and superconducting pure phase. The zero critical temperature of the Tl-Re sample is 99.9 K and is practically the same as the critical temperature of the rhenium free sample: 99.5 K. The Tl-Re superconductor exhibits two peaks of the absorption part of AC susceptibility in the vicinity of the critical temperature in contrary to the rhenium free sample. The first peak placed in higher temperature is related to intragranular properties while the second peak is connected with the intergranular one. The critical current densities versus temperature were calculated from AC susceptibility as well as from the magnetization loops measurements using the Bean's critical state model. The Tl-Re film exhibits the higher critical current in comparison to the rhenium free thallium based film.

6

Influence of Carbon on Spin Reorientation Processes in Er_{2-x}R_xFe_{14}C (R~=~Gd, Pr) - Mössbauer and Magnetometric Studies

39%

Pędziwiatr A., Krawiec K., Bogacz B., Kapusta C., Przewoźnik J., Kaczorowski D., Talik E.

Acta Physica Polonica A

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2011

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vol. 119

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issue 1

48-51

EN

The Er_{2-x}R_{x}Fe_{14}C (R=Gd, Pr) polycrystalline compounds have been synthesized and investigated with ^{57}Fe Mössbauer spectroscopy and magnetic measurements. The spin reorientation phenomena were studied extensively by narrow step temperature scanning in the neighborhood of the spin reorientation temperature. Obtained Mössbauer spectra were analyzed using a procedure of simultaneous fitting and the transmission integral approach. Consistent description of Mössbauer spectra were obtained, temperature and composition dependencies of hyperfine interaction parameters and subspectra contributions were derived from fits and the transition temperatures were determined for all the compounds studied. Initial magnetization versus temperature measurements (in zero and non-zero external field) for Er_{2-x}Gd_{x}Fe_{14}C compounds allowed to establish the temperature regions of reorientation, change of magnetization value during the transition process. The results obtained with different methods were analyzed and the spin arrangement diagrams were constructed. Data obtained for Er_{2-x}Gd_{x}Fe_{14}C were compared with those for Er_{2-x}Gd_{x}Fe_{14}B series.

7

Magnetoresistance Study of c-Axis Oriented YBCO Thin Film

33%

Chrobak M., Woch W., Kowalik M., Zalecki R., Giebułtowski M., Przewoźnik J., Kapusta C., Szwachta G.

Acta Physica Polonica A

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2017

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vol. 131

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issue 4

1018-1020

EN

The c-axis orientation YBa₂Cu₃O_δ thin film was prepared directly on MgO substrate by the pulse laser deposition. The thickness of the film is 170 nm. The superconducting critical temperature is T_{c50%}=87.5 K and the width of superconducting transition is ΔT = 1.8 K. The temperature dependences of magnetoresistance were measured up to 90 kOe. The widths of the transition to the superconducting state versus applied magnetic field were derived and they were fitted using the formula: Δ T=CH^m +Δ T₀. The irreversibility fields as a function of temperature were obtained and fitted by the de Almeida and Thouless-like equation: H_{irr}=H_{irr0}(1-T/T_{c0})^n. The irreversibility field at the liquid nitrogen temperature was calculated and it is H_{irr}=43.8 kOe when the applied magnetic field is parallel to the c-axis.

8

Structural, Thermal, Magnetic, and Transport Properties of (La_{2/3}Ca_{1/3})(Mn_{1-x}Sn_x)O_{3-δ} Compounds

33%

Przewoźnik J., Chmist J., Kolwicz-Chodak L., Tarnawski Z., Kołodziejczyk A., Krop K., Kellner K., Gritzner G.

Acta Physica Polonica A

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2004

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vol. 106

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issue 5

665-680

EN

The structural, magnetic, and electrical transport properties of Sn-doped manganite La_{0.67}Ca_{0.33}Mn_{1-x} Sn_xO_{3-δ} (x=0, 0.01, 0.03, andδ≈0.06) compounds were studied using X-ray powder diffraction, scanning electron microscopy, AC susceptometer and vibrating sample magnetometer measurements as well as four-probe resistance measurements. The specific heat was measured by the heat-pulse method. The Curie temperature T_C and the metal-insulator transition temperature T_{M-I} decreased nonlinearly with increasing Sn content. The T_C and T_{M-I} values, for the x=0, 0.01, and 0.03 compounds were separated by 18.2 K, 66.3 K, and 10 K, respectively. The resistivity above T_C for all of these compounds followed the Mott variable-range-hopping model. This allowed the estimation of the localization lengths of 2.2Å (x = 0), 1.33Å (x=0.01) and 1.26Å (x=0.03). The x=0 and x=0.01 compounds exhibited anomalies of R(T) at corresponding T_C and allowed the separation of the magnitude of the purely magnetic contribution to the resistance which for x=0 was≈5 .7Ω and for x=0.01,≈22 .4Ω. The specific heat of the Sn-free sample exhibited a sharp peak at T_C. With increasing Sn content the peak at T_C broadened and the area under the peak decreased. For x= 0.03 the peak was hardly detectable. Our results on La_{0.67}Ca_{0.33} Mn_{1-x}Sn_xO_3 reveal that a small substitution of Sn^{4+} for Mn^{4+} suppresses double exchange interactions and strongly affects the magnetic, thermal, and transport properties of the parent compound.

9

Ion Irradiation of Oxidized FeCoZr-CaF₂ Nanocomposite Films for Perpendicular Magnetic Anisotropy Enhancement

33%

Kasiuk J., Fedotova J., Przewoźnik J., Kapusta C., Skuratov V., Svito I., Bondariev V., Kołtunowicz T.

Acta Physica Polonica A

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2017

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vol. 132

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issue 2

206-209

EN

The paper is focused on the results of Xe ions irradiation of nanocomposite FeCoZr-CaF₂ films synthesized in the oxygen-containing atmosphere. Combined influence of nanoparticles partial oxidation and ion irradiation with different fluences on the crystalline structure, phase composition and magnetic anisotropy is analysed by X-ray diffraction, the Mössbauer spectroscopy and vibrating sample magnetometry. The origin of the detected progressive enhancement of perpendicular magnetic anisotropy as the result of films oxidation and irradiation is discussed in the context of formation of nanoparticles oxide shells and ion tracks along the films normal.

Refine search results

NMR (^{55}Mn, ^{139}La) and Mössbauer Spectroscopy (^{119}Sn) Studies of (La_{0.67}Ca_{0.33})(Mn_{1-x}Sn_x)O_{3-δ} Compounds

Magnetism and Specific Heat of TmRhX (X = Ga, Ge) Compounds

High-Pressure Mössbauer Studies of Magnetism in ScFe_2 and Sc_{0.4}Ti_{0.6}Fe_2 Laves Phases

Magnetic Properties of Dy_{11}Si_4In_6

Magnetization, Susceptibility and Critical Currents of (Tl_{2-x}Re_{x})Ba_{2}CaCu_{2}O_{y} Thin Films

Influence of Carbon on Spin Reorientation Processes in Er_{2-x}R_xFe_{14}C (R~=~Gd, Pr) - Mössbauer and Magnetometric Studies

Magnetoresistance Study of c-Axis Oriented YBCO Thin Film

Structural, Thermal, Magnetic, and Transport Properties of (La_{2/3}Ca_{1/3})(Mn_{1-x}Sn_x)O_{3-δ} Compounds

Ion Irradiation of Oxidized FeCoZr-CaF₂ Nanocomposite Films for Perpendicular Magnetic Anisotropy Enhancement