Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl

Refine search results

Journals help

  1. 27 Acta Physica Polonica A

Years help

  1. 6 2017

  2. 2 2014

  3. 3 2012

  4. 6 2010

  5. 3 2009

More...
Authors help

  1. 27 Reiffers M.

  2. 5 Giovannini M.

  3. 5 Kowalczyk A.

  4. 5 Šebek J.

  5. 4 Flachbart K.

More...
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 27

Number of results on page
first rewind previous Page / 2 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 2 next fast forward last
1
Content available remote

Approximation of Electrical and Magneto Transport Properties of LSMO Thin Films

100%
Štrbík V., Reiffers M., Chromik Š., Španková M.
|
|
vol. 126
|
issue 1
210-211
EN
We have used a three term polynomial expression to approximate electrical and magneto transport properties of epitaxial La_{0.67}Sr_{0.33}MnO_{3} (LSMO) thin films in wide temperature range (2-350 K) and in magnetic field up to 9 T. The first term is determined by a low temperature (T<20 K) residual resistivity ρ_{0} and this term is magnetic field independent. The second term describes the electron-electron scattering in LSMO, it shows ~ T^{2} dependence of resistivity up to temperature about 160 K and depends only weakly on magnetic field. The third term, proportional to ~ T^{4.5} dependence, describes a significant increase of resistivity in temperature range 160-350 K and due to its sensitivity to applied magnetic field it is possible to approximate temperature dependence of magnetorestivity below 350 K.
2
Content available remote

Magnetic and Heat Capacity Study of the new Gd_{1-x}Ce_xNi₅ Series

100%
Dzubinska A., Reiffers M., Espeso J., Rodríguez Fernández J.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 4
997-999
EN
We have prepared a new system of Gd_{1-x}Ce_xNi₅ polycrystalline samples with concentrations x =0, 0.2, 0.5, and 0.8 in order to study the influence of different rare-earths substitutions on the ground state connected with spin fluctuations. GdNi₅ is a ferromagnetic compound with T_{C}=31.8 K and CeNi₅ is a well-known spin fluctuation compound without magnetic ordering down to the lowest temperatures. X-ray diffraction study confirms the hexagonal crystal structure and the single phase samples. Magnetic properties (M(T),M(B)) show that an increasing content of Ce depresses the transition temperature, T_{C}, down to 4.9 K for x=0.8. The heat capacity measurements confirmed these results.
3
Content available remote

Low Temperature Magnetic Ordering in NdAgAl₃

100%
Nallamuthu S., Džubinská A., Reiffers M., Nagalakshmi R.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 4
1015-1017
EN
We present the detailed study of magnetic, thermodynamic, and transport properties of polycrystalline NdAgAl₃. The compound crystallizes in BaNiSn₃-type tetragonal structure with the space group I4mm. Magnetic, heat capacity and transport measurements indicate the possible antiferromagnetic nature of the ordering below 2 K. The compound shows the Schottky anomaly in heat capacity data. Magnetoresistance is negative at low temperature.
4
Content available remote

Point Contact Properties of R_3Pd_{20}X_6 (R = La, Ce; X = Si, Ge) Cage Compounds

100%
Čurlik I., Strydom A., Reiffers M.
|
|
issue 5
907-909
EN
Point-contact spectroscopy measurements have been performed on the R_3Pd_{20}X_6 (R = La, Ce; X = Si, Ge) cage compounds. In case of La the characteristic phonon energies have been obtained in agreement with that of the Raman scattering. In Ce_3Pd_{20}Si_6 we have observed asymmetric behaviour of dV/dI(V) dependences which was observed in non-Fermi liquid compound. In Ce_3Pd_{20}Ge_6 we have observed maxima at crystalline electric field energies, influenced by magnetic field. This is connected with quadrupolar ordering transition.
5
Content available remote

Study of Magnetic Contribution to the Heat Capacity of YbCu_4Ni

100%
Čurlik I., Reiffers M., Giovannini M.
Acta Physica Polonica A
|
2012
|
vol. 122
|
issue 1
3-5
EN
An investigation of the magnetic heat capacity of the heavy-fermion compound YbCu_4Ni up to 0.4 K is presented. The novel compound LuCu_4Ni, isotypic with YbCu_4Ni has been synthesized and characterized, and its heat capacity was measured in order to subtract the lattice contribution from the previously measured heat capacity data of YbCu_4Ni.
6
Content available remote

Crystal Structure and Magnetic Properties of new Eu-Pd-Sn Compounds

88%
Čurlík I., Gastaldo F., Giovannini M., Strydom A., Reiffers M.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 4
1003-1005
EN
We report on the synthesis, crystal structure determination, and magnetic susceptibility measurements of Eu₃Pd₂Sn₂, EuPd₂Sn₄, and EuPdSn₂. For all three compounds a divalent state of Eu ions was obtained from the fitting of the magnetic susceptibilities. At low temperatures Eu₃Pd₂Sn₂, EuPd₂Sn₄, and EuPdSn₂ order magnetically at 23, 12, and 13 K, respectively.
7
Content available remote

Transport and Magnetic Properties of YbCu_4Ni

88%
Čurlik I., Mát'ošová Š., Il'kovič S., Reiffers M., Giovannini M.
Acta Physica Polonica A
|
2012
|
vol. 122
|
issue 1
6-10
EN
The results on the influence of magnetic field on the electrical resistivity ρ(T) of the heavy fermion YbCu_4Ni in the temperature range 0.4-300 K are presented. We have observed a Kondo-like behaviour below 10 K with a minimum in ρ(T) at about 60 K. An applied magnetic field depresses this behaviour, and a maximum in ρ(T) appears similarly to the maximum observed in heat capacity. The observed electrical magnetoresistance shows negative values in all applied magnetic fields and with increasing temperature its absolute magnitude increases. Moreover, we extended our previous susceptibility measurements up to high temperatures of 1000 K, in order to study possible mixed valence behaviour, which however was not observed.
8
Content available remote

Low Temperature Properties of the Ce_{1-x}La_{x}NiAl_4

76%
Toliński T., Kowalczyk A., Reiffers M., Šebek J., Šantavá E., Curlik I., Ilkovič S.
|
|
issue 5
933-935
EN
Measurements of the heat capacity in ultralow temperatures (down to 350 mK) have been carried out for Ce_{1-x}La_{x}NiAl_4. The paramagnetic behavior above about 30 K can be well described by the Curie-Weiss magnetic susceptibility. The undoped CeNiAl_4 compound is a known heavy fermion system with a large electronic specific heat coefficient (γ = 0.5 J mol^{-1} K^{-2}) and the Kondo temperature in the range 30-80 K. In the case of the Ce_{0.8}La_{0.2}NiAl_4 and Ce_{0.6}La_{0.4}NiAl_4 compounds a peak in C/T appears below 2 K, which is strongly damped by the magnetic field. It is probably connected with the Kondo and/or magnetic interactions and the electronic specific heat coefficient is 0.19 J mol^{-1} K^{-2} (0.43 J mol^{-1} K^{-2}) for x = 0.2 (x = 0.4) at T → 0. The value determined above the peak, at temperature for which the magnetic field starts to decrease γ ( ≈ 3 K), is about 0.5 J mol^{-1} K^{-2} and the effect of the magnetic field can be well analyzed in frames of the single-ion Kondo model.
9
Content available remote

Point-Contact Spectroscopy of Crystalline Electric Field of Heterocontacts PrB_6 and NdB_6 with Pt

76%
Vasil'ová M., Pristáš G., Reiffers M., Flachbart K., Rusz J., Shitsevalova N.
Acta Physica Polonica A
|
2008
|
vol. 113
|
issue 1
267-270
EN
Point-contact spectra of single crystals PrB_6 and NdB_6 are presented. We observed maxima connected with crystalline electric field excitations in agreement with previous results for applied voltage V>8 mV. Moreover, we observed maxima at 6 mV (PrB_6) and 3 mV (NdB_6), which are probably connected with phonon modes. Moreover, we observed phonon peak at 10.6 mV in PrB_6. Further measurements in magnetic fields and crystalline electric field calculations are necessary.
10
Content available remote

Magnetic and Structural Characterization of NiXSb (X = Mn, Cr) Heusler Ribbon

76%
Ryba T., Vargova Z., Ilkovic S., Reiffers M., Kravcak J., Gyepes R., Varga R.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 4
857-859
EN
Half-Heusler alloys with composition NiMnSb and NiCrSb have been prepared by rapid-quenching method. NiMnSb half-Heusler alloy is characterized by single phase C1_{b} with polycrystalline structure while crystalline structure of NiCrSb shows multiphase system. Magnetic measurements indicated high anisotropy and easy magnetization direction in the parallel direction with respect to ribbon axis for NiMnSb alloy while paramagnetic behavior appears for NiCrSb alloy down to 50 K.
11
Content available remote

Heat Capacity of Heavy Fermion Compound CeCu_4Ga in High Magnetic Fields

76%
Kowalczyk A., Toliński T., Reiffers M., Zapotoková M., Falkowski M., Gažo E.
Acta Physica Polonica A
|
2009
|
vol. 115
|
issue 1
123-125
EN
The heat capacity in the applied magnetic field up to 9 T, susceptibility and magnetization of polycrystalline CeCu_{4}Ga are presented. Magnetic ordering was not observed down to 2 K. For temperature T < 200 K a Curie-Weiss behavior is observable giving an effective magnetic moment μ_{eff} =2.53 μ_{B}/f.u. The experimental value of μ_{eff} is close to the calculated one for a free Ce^{3+} ion (μ_{eff} = 2.54 μ_{B}/f.u.), thus indicating the presence of well localized magnetic moments carried by the stable Ce^{3+} ions. At low temperatures the electronic heat capacity coefficient value depends strongly on the temperature range used for the extrapolation and applied magnetic field. We observe a typical heavy fermion behavior with γ value of about 380 mJ mol^{-1} K^{-2} obtained from extrapolation to T = 0 K of the temperature range above 7 K. However, extrapolation of the lowest temperatures range yields the γ value of 3.3 J mol^{-1} K^{-2}.
12
Content available remote

Heat Capacity Studies of NdNi_4Si Compound

76%
Falkowski M., Reiffers M., Zapotoková M., Kowalczyk A., Toliński T., Gažo E.
Acta Physica Polonica A
|
2009
|
vol. 115
|
issue 1
126-128
EN
The study of the heat capacity of the intermetallic compound NdNi_{4}Si including the effect of the magnetic field is reported. This compound crystallizes in the hexagonal CaCu_5-type structure, space group P6/mmm. NdNi_{4}Si is ferromagnetic with T_C = 8 K and the saturation magnetic moment of 1.5 μ_{B}/f.u. at 4.2 K (in H = 9 T). The heat capacity was analyzed considering the electronic contribution, the Schottky anomaly, and the lattice contributions in the frames of the Debye model. The scheme of the energy levels created by the crystal electric field split is determined from the Schottky contribution to the specific heat. NdNi_{4}Si was characterized by the electronic heat capacity coefficient γ = 85 mJ/(mol K^2) and the Debye temperature Θp_D = 325 K.
13
Content available remote

Point-Contact Spectroscopy of Ce_{1-x}RE_{x}Ni_{5} (RE = Pr, Nd)

76%
Kačmárová T., Reiffers M., Garcia Soldevilla J., Goméz Sal J., Espeso J., Blanco J.
Acta Physica Polonica A
|
2000
|
vol. 97
|
issue 5
795-798
EN
We report on the study of the electron-quasiparticle interaction function in Ce_{1-x}RE_{x} Ni_{5} (RE = Pr, Nd) pseudobinary compounds for x = 0, 0.2, 0.5, 0.8, and 1 measured by means of point-contact spectroscopy. The measured point-contact spectra (d^{2}V/dI^{2} - directly proportional to the electron- quasiparticle interaction function) of the heterocontacts between Ce_{1-x} RE_{x}Ni_{5} and Cu in the ballistic regime are presented.
14
Content available remote

Strong Electronic Correlations in a New Yb-Based Compound: YbCu_4Ni

76%
Čurlik I., Reiffers M., Giovannini M., Gažo E., Šebek J., Šantavá E.
|
|
issue 5
919-921
EN
Heat capacity measurements performed on the new ternary compound YbCu_4Ni indicate for this compound strong electronic correlations with possible antiferromagnetic phase transition below 0.5 K. Susceptibility and magnetisation measurements above 2 K show no magnetic ordering.
15
Content available remote

Electron Transport and Point Contact Spectroscopy of Cubic DyCu_{5}

76%
Nenkov K., Idzikowski B., Ilkovic S., Kačmarčiková E., Reiffers M., Müller K.
Acta Physica Polonica A
|
2000
|
vol. 97
|
issue 5
843-846
EN
The electron transport properties and point contact spectra of melt-spun DyCu_{5} with the cubic phase (structure type AuBe_{5}, space group $F\overline{4}3m$) were investigated. It was found by ac-susceptibility measurements that below a transition temperature T_{m}=6.5 K this phase shows metamagnetism. Between T_{m} and T_{C}=14.5 K a spontaneous magnetization is found. Our measurements of electrical resistivity confirm the existence of two magnetic phase transitions in the compound. Furthermore, we present point contact spectra of DyCu_{5}-Cu heterocontacts which are directly proportional to the electron-quasiparticle interaction function. Apart from a peak at about 18 meV, which is characteristic of electron-phonon interaction in pure Cu, we observed a series of additional maxima at lower energy, which are connected with the allowed 4f-transitions from the ground state to excited crystalline electric field levels.
16
Content available remote

Magnetocaloric Effect in Geometrically Frustrated Magnetic Compound HoB_{12}

76%
Snyman J., Flachbart K., Gabani S., Reiffers M., Shitsevalova N., Siemensmeyer K., Strydom A.
|
|
issue 5
873-874
EN
The magnetocaloric effect of frustrated antiferromagnetic HoB_{12} is calculated. The isothermal entropy change Δ S characterising the magnetocaloric effect shows a small positive change upon magnetisation below the transition temperature T_{N}, indicating a small inverse magnetocaloric effect. At T_{N}, Δ S shows clear scaling behaviour with the applied magnetic field. The adiabatic temperature change Δ T shows paramagnetic behaviour above T_{N}, despite strong magnetic correlations that persist in this temperature region. The adiabatic temperature change calculated for HoB_{12} is appreciable.
17
Content available remote

Magnetocaloric Effect in Nanostructured Pr_2Fe_{17} and Nd_2Fe_{17} Synthesized by High-Energy Ball-Milling

76%
Alvarez P., Sánchez-Marcos J., Sanchez Llamazares J., Franco V., Reiffers M., Blanco J., Gorria P.
|
|
issue 5
867-869
EN
Nanocrystalline Pr_2Fe_{17} and Nd_2Fe_{17} powders with rhombohedral Th_2Zn_{17}-type crystal structure and average particle sizes around 20 nm have been obtained by high-energy ball milling. While the bulk alloys show a well-defined and sharp drop in the low-field magnetization curve at the Curie temperature, T_{C} = 285 K (Pr) and 335 K (Nd), the ball-milled samples exhibit a substantial broadening of the ferro-to-paramagnetic transition due to a considerable augmentation of the disordered inter-grain boundaries. The latter results in an increase of more than 25% in the values of the full width at half maximum of the temperature dependence of the magnetic entropy change maintaining almost unchanged the relative cooling power.
18
Content available remote

Pressure Effect on Yb-Based Strongly Correlated Electron Systems

64%
Mito T., Otani M., Nakamura M., Koyama T., Wada S., Kotegawa H., Kobayashi T., Idzikowski B., Reiffers M., Sarrao J.
Acta Physica Polonica A
|
2009
|
vol. 115
|
issue 1
47-52
EN
We studied pressure effects on YbCu_5 and YbInCu_4, good examples of the Yb-based compounds to investigate the nonmagnetic-magnetic transition in Yb-based strongly correlated electron systems. With increasing pressure, the low-temperature Fermi liquid state of YbCu_5 is gradually suppressed, suggesting the second-order like nonmagnetic-magnetic transition around the pressure of 5-6 GPa. On the other hand, in YbInCu_4 which has a pressure-induced magnetic ordered ground state above P_C=2.45 GPa, both high-temperature paramagnetic and low-temperature intermediate valence phases are insensitive to pressure. Our results confirm the first-order nature of the transition between the intermediate valence and magnetic ordered phases with pressure.
19
Content available remote

Structural and Physical Properties of the new Stannide Yb₃Pd₄Sn₁₃

64%
Gastaldo F., Giovannini M., Strydom A., Djoumessi R., Čurlík I., Reiffers M., Solokha P., Saccone A.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 4
1006-1008
EN
Among the new discovered intermetallics in the Yb-Pd-Sn system, the cubic phase Yb₃Pd₄Sn₁₃, with a lattice parameter of 0.9743(5) nm, emerges as a new member of the R₃T₄Sn₁₃ family (R = rare earth element, T = transition metal) crystallizing in the Yb₃Rh₄Sn₁₃-structure type. The effective magnetic moment μ_{eff}=1.84 μ_{B}/Yb is strongly reduced. Moreover, measurements of magnetic properties, specific heat and resistivity indicate superconductivity below 2.4 K. This compound is found to exhibit a strongly enhanced electronic specific heat at low temperature from which we infer a possible low-lying magnetic phase transition or other source of magnetic entropy.
20
Content available remote

Characterization of New U-Ni-X₂ Splats and Study of their Physical Properties

64%
Molčanová Z., Mihalik M., Mihalik M., Reiffers M., Džubinská A., Huráková M., Kavečanský V., Paukov M., Havela L.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 4
994-996
EN
We explored the crystal structure, magnetic, and transport properties of UNiX₂ (X = Ge, Si) materials, which were prepared by a conventional metallurgical technique and by rapid solidification - splat cooling. The UNiSi₂ splat is mostly single phase, containing only small traces of a minority phase. Magnetic and electrical properties of the splat resemble properties of samples, which were prepared by conventional methods, exhibiting a ferromagnetic transition at about 91 K and similar temperature dependence of resistivity. The coercive field of μ₀H_c=4.25 T is much enhanced due to the magnetic anisotropy introduced by the sample preparation technique. The Barkhausen jumps were observed on the hysteresis loop. Magnetization of the sample does not saturate in fields up to μ₀H=9 T. The phase structure of UNiGe₂ splat is not completely solved and will be subject of our study in future. Our preliminary results indicate the presence of completely new phase with tetragonal crystal structure and antiferromagnetic ordering below 54 K.
first rewind previous Page / 2 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.