Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 5

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

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

Experimental Investigation of Small-Scale Magnetocaloric Refrigerator

100%
Kaštil J., Tětek J., Tuček A.
Acta Physica Polonica A
|
2013
|
vol. 124
|
issue 4
740-744
EN
The small-scale magnetocaloric cooling device was developed at Czech Technical University in Prague. The magnetocaloric small-scale cooling system was designed as push-pull system with two permanent magnets with field of about 0.85 T. The construction offers a possibility to alter independently many parameters of the cooling process and it ensures easy way to change working material and design of heat exchangers. The measurements were performed with 35 g of gadolinium as a working material and ethanol as heat transfer liquid. Device was successfully operated at room temperature with maximal heat span of 3.1 K. In the article we report design of the machine and first measurement performed on it.
2
Content available remote

Magnetocaloric Effect of the Tb_{1-x}Y_{x}NiAl and TbNiAl_{1-y}In_{y} Series

100%
Kaštil J., Javorský P., Klicpera M.
|
|
issue 5
888-890
EN
We have studied the development of the magnetocaloric effect in the (Tb,Y)NiAl and TbNi(Al,In) series as determined from magnetization measurements. The transition from antiferromagnetic order in TbNiAl to ferromagnetic order in Tb_{0.7}Y_{0.3}NiAl is accompanied by increase of the maximum entropy change from - 4.1 to - 4.4 J kg^{-1} K^{-1}. In the TbNi(Al,In) series, the change of uniaxial anisotropy in TbNiAl to the easy-plane anisotropy in TbNiIn leads to broadening of the magnetocaloric effect accompanied with large increase of the relative cooling power from 66 to 120 J kg^{-1}.
3
Content available remote

Magnetocaloric Effect in Materials with the First Order Transitions - Direct Measurements

88%
Kamarád J., Kaštil J., Arnold Z., Javorský P., Sechovský V.
|
|
issue 5
1000-1001
EN
The results of direct measurements of the magneto-caloric characteristics Δ T_{ad} and the indirect determination of Δ S_{m} of pure Gd around the Curie temperature and of the FeMnP_{0.45}As_{0.55} and Ni_{45}Co_5Mn_{31}Ga_{19} intermetallics in the vicinity of the first order magnetic and structural phase transitions are presented and discussed. A pronounced temperature and field dependence of the first order transitions in the studied materials manifests restrictions applying these materials in magnetic refrigeration techniques. An effective use of the Ericsson and the Brayton refrigeration cycles with FeMnP_{0.45}As_{0.55} in the role of a refrigerant is discussed.
4
Content available remote

Spin Disordered Resistivity of the Heusler Ni₂MnGa-based Alloys

88%
Kamarád J., Kaštil J., Albertini F., Fabbrici S., Arnold Z.
Acta Physica Polonica A
|
2017
|
vol. 131
|
issue 4
1072-1074
EN
Electrical resistivity of the selected Heusler off-stoichiometric (NiCo)₂Mn(GaIn) alloys was studied in a wide range of temperature and magnetic field. A step-like change of resistivity (Δρ ≈24 μΩcm) was detected in the off-stoichiometric Ni_{1.85}Mn_{1.21}Ga_{0.94} alloy at temperature of martensitic structural transition. This Δρ is much more significant than one in the stoichiometric Ni₂MnGa alloy. In the case of the off-stoichiometric (NiCo)₂Mn(GaIn) alloys, an enormous change of resistivity, Δρ ≈ 200 μΩcm, accompanies the structural transition. Simultaneously, the maximum of the spin disordered resistivity ρ_{sd}(T) of austenite phase of the alloys is slightly dependent on composition of the alloy and vary from ≈30 μΩcm up to ≈45 μΩcm, in good agreement with theoretical calculations. Due to high sensitivity of the structural transition temperature of the alloys to magnetic field, the very pronounced magnetoresistance effects have been observed in the studied alloys.
5
Content available remote

Pressure Influence on Magnetic Properties of TbNiAl

88%
Javorský P., Prchal J., Klicpera M., Kaštil J., Míšek M.
|
|
vol. 126
|
issue 1
280-281
EN
We have investigated the effect of hydrostatic pressure on magnetic properties of TbNiAl, crystallizing in hexagonal ZrNiAl-type structure. TbNiAl orders antiferromagnetically below T_{N}=45 K and undergoes further magnetic phase transition to another AF phase at T_{1}=23 K. The magnetic field of B_{c} ≅ 0.3 T applied along the c-axis at 2 K leads to the transition to ferromagnetic order. By applying the hydrostatic pressure, both T_{N} and T_{1} remain almost unaffected whereas B_{c} shows a strong increase. The hydrostatic pressure stabilizes the antiferromagnetic state which can be related to development of structural parameters.
first rewind previous Page / 1 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.