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1

Electronic Structure and Magnetic Properties of La_{1-x}Ce_{x}Pb_3 and La_{1-x}Pr_{x}Pb_3 Alloys

100%

Jezierski A., Kaczkowski J., Cichorek T.

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vol. 125

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issue 1

111-114

EN

The electronic structure and magnetic properties of La_{1-x}Ce_{x}Pb_3 and La_{1-x}Pr_{x}Pb_3 are studied using the spin-polarized relativistic Korringa-Kohn-Rostoker coherent potential approximation method within the local spin density approximation. The calculated density of states at the Fermi level increases with the increase of the concentration. The dependence of spin and orbital magnetic moments of La_{1-x}Ce_{x}Pb_3 and La_{1-x}Pr_{x}Pb_3 (0 < x < 1) on the concentration is also reported. The densities of states at the Fermi energy are dominated by Ce(Pr) 4f_{5/2} and 4f_{7/2} states.

2

Electronic and Magnetic Effects on Cu Doping Ti_2NiAl Heusler Alloy: A First-Principles Study

100%

Wei X., Chu Y., Sun X., E Y., Song T., Guo P.

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vol. 126

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issue 3

795-798

EN

We investigate the effect of the electronic and magnetic properties on nonmagnetic Cu-3d atoms doping the Heusler alloy Ti_2Ni_{1-x}Cu_xAl (0 ≤ x ≤ 1) using first-principles calculations. The optimized lattice constants are consistent with the Vegard law, and energies of doped systems become more lower as the increase of x concentration. A critical transition diagram from half-metallic to metallic characters is discussed. In addition, the magnetic interactions between p and d states are illustrated. Finally, magnetic moments are given as a function of x value, which implies that the Slater-Pauling rule is obeyed at low Cu content (x ≤ 0.2).

3

Electronic Band Structure and Calculated Photoemission Spectra of USi_{3} Compound

100%

Morkowski J., Szajek A., Jezierski A.

Acta Physica Polonica A

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1997

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vol. 92

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issue 2

303-306

EN

The electronic band structure for USi_{3} was recalculated for varying ratios of the Wigner-Seitz radii, for U and Si atoms. The partial densities of states were used to calculate photoemission spectra which were compared with available experimental data.

4

Photoemission Electronic States of (Mn_{1-x}Fe_x)_5Si_3

100%

Penc B., Zalecki R., Jezierski A., Szytuła A., Kołodziejczyk A., Ivanov V.

Acta Physica Polonica A

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2005

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vol. 107

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issue 6

967-976

EN

The core-level and valence band electronic states studies of single crystalline transition metal silicides (Mn_{1-x}Fe_x)_5Si_3 (x=0 and 0.05) by the X-ray and ultraviolet photoemission spectroscopies are reported. The Mn 2p core-level spectra for both compounds were ascribed to the relevant Mn sites in their crystal structure. The valence band spectra were compared with the result of ab-initio band calculations using the tight-binding linear muffin-tin orbital method. It was concluded that the enhancement of the spectral density within the 2 eV binding energy region below the Fermi energy comes from the effect of strongly correlated Mn 3d electrons.

5

Analytical Description of SMA Actuator Dynamics based on Fermi-Dirac Function

100%

Kluszczyński K., Kciuk M.

Acta Physica Polonica A

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2017

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vol. 131

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issue 5

1274-1279

EN

The paper deals with possible application of the very promising SMART material - shape memory alloy. At the beginning the laboratory stand for investigation on dynamic behaviour of a SMA linear actuator is presented and results of measurements for the chosen SMA actuator F2000 are depicted and discussed. In the next stage the authors propose to use the so-called Fermi-Dirac function for description of SMA linear actuator dynamics. Applying this function for determining basic performance curve: shortening Δ L versus time t for different loads F requires proper modification of the Fermi-Dirac function and its conversion in the one-parameter family (with parameter F). Coefficients of this family are determined with the help of Hooke-Jeeves optimization algorithm and on the basis of experimental findings separately for activation and deactivation process. The both derived expressions were validated by additional laboratory investigations. Finally, the elaborated descriptions was employed in design procedure of a robot gripper. It was shown that the results of measurements for the gripper prototype are in satisfactory agreement with the results of calculations.

6

Electronic Structure and Magnetic Exchange Interaction in Fe₂NiAs Compound

100%

Wei X.-P., Zhang Y.-L., Sun X.-W., Song T., Zhu X.-F.

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EN

Using the spin-polarized relativistic Korringa-Kohn-Rostoker method, we study the electronic and magnetic properties of Fe₂NiAs compound with the Hg₂CuTi structure. Electronic calculations reveal the d-d orbital hybridization taking an important role in the compound. The calculated magnetic moments, which contain the spin and orbital moments, are primarily carried by Fe atoms located in A and B sites. The orbital moment of Fe₂NiAs system is rather small due to the cause of orbital quenching, implying a weak spin-orbit coupling. Simultaneously, we also study the influence of lattice constant on the magnetic moment, it is found that both spin and orbital moments are sensitive to the changes of lattice constants, i.e., the moments become larger as the expansion of lattice constant, indicating the enhancement of spin-orbit coupling effect. In addition, we investigate the magnetic interactions between the constituents to obtain the Heisenberg exchange coupling parameters. It is noted that the interactions are dominated by a strong exchange between Fe atoms. Finally, we acquire the Curie temperatures of Fe₂NiAs compound under different lattice constants by using mean field approximation.

7

Characterization of Bimetallic Systems with UPS and PAX: Gold on Platinum and Palladium Surfaces

88%

Moors M., Kobiela T., Krupski A., Becker C., Wandelt K.

Acta Physica Polonica A

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2008

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vol. 114

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issue S

S-77-S-92

EN

In the present study the thermal behavior of ultrathin Au films deposited on different noble metal single crystal surfaces was studied by means of ultraviolet photoelectron spectroscopy and photoemission of adsorbed xenon. The primary goal of this work was to demonstrate the power of photoemission of adsorbed xenon as an easy to handle and very surface sensitive technique for the characterization of multi-component systems. All investigated systems, Au-Pt(111), Au-Pd(111) and Au-Pd(110) show a particular dependence of their electronic and structural properties on the annealing temperature. Au multilayer films with a thickness of 3 monolayer prepared at 150 K undergo in all cases a smoothening by annealing up to room temperature. While on Pd this effect is mainly detectable on the topmost atomic layer the ordering process on Pt is also affecting the deeper layers. Further annealing of the Au-Pd system to 450 K and the Au-Pt system to 750 K, respectively, results in the onset of the alloying process at the interface between metal film and substrate. After annealing to 650 and 950 K, respectively, the alloying finally extends to the very surface. The complete loss of Au from the surface can be detected at 1050 K on Pd and at 1150 K on Pt. The orientation of the substrate has only a weak influence, showing up e.g. in additional electronic states of the not alloyed Au-Pd(111) and Au-Pd(111) systems. Adsorption of CO as a probe molecule illustrates the formation of different adsorption sites on the bimetallic systems during the Au diffusion process.

Refine search results

Electronic Structure and Magnetic Properties of La_{1-x}Ce_{x}Pb_3 and La_{1-x}Pr_{x}Pb_3 Alloys

Electronic and Magnetic Effects on Cu Doping Ti_2NiAl Heusler Alloy: A First-Principles Study

Electronic Band Structure and Calculated Photoemission Spectra of USi_{3} Compound

Photoemission Electronic States of (Mn_{1-x}Fe_x)_5Si_3

Analytical Description of SMA Actuator Dynamics based on Fermi-Dirac Function

Electronic Structure and Magnetic Exchange Interaction in Fe₂NiAs Compound

Characterization of Bimetallic Systems with UPS and PAX: Gold on Platinum and Palladium Surfaces