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1

Mechanical Properties of Tetragonal and Orthorhombic Phases of Quasi-One-Dimensional Antiferromagnet KCuF_{3}

100%

Legut D., Wdowik U.

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vol. 126

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issue 1

14-15

EN

The density functional theory was used to calculate the elastic constants for the two tetragonal (a-type) and (d-type), and the orthorhombic structures of KCuF_{3}. Based on the single elastic constants the polycrystalline mechanical properties such as bulk, shear, Young moduli and Poisson ratio using Reuss-Voigt-Hill averaging method were estimated. Furthermore, the sound transverse and longitudional velocities (along the a-axis and c-axis) were calculated and the Debye temperatures were determined for all three investigated phases.

2

Impurity Effect on Charge and Spin Density in α-Fe - Comparison between Cellular Model, Ab Initio Calculations and Experiment

100%

Błachowski A., Wdowik U.

Acta Physica Polonica A

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2011

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vol. 119

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issue 1

24-27

EN

The influence of the impurity substituted on the regular site in the BCC α-Fe on charge and spin density on the adjacent iron nuclei has been studied by the ab initio method within framework of the full-potential linearized augmented plane-wave formalism applying density functional theorem. Results were correlated with the phenomenological cellular atomic model of Miedema and van der Woude and with the Mössbauer spectroscopy experimental data.

3

Exchange Interactions in a Low-Dimensional Magnetic System Cu(H_{2}O)_{2}(en)SO_{4}

81%

Sýkora R., Legut D., Wdowik U.

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vol. 126

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issue 1

50-51

EN

We report a theoretical ab-initio investigation of the exchange interaction between Cu atoms in Cu(H_{2}O)_{2}(en)SO_{4}, en=C_{2}H_{8}N_{2}(ethylenediamine), an insulating magnetic material. Unlike previous experimental studies which describe the system as a quasi-two-dimensional antiferromagnet, our results, based on the mapping of the system onto an effective Heisenberg model, suggest a quasi-one-dimensional character of magnetism, with the exchange coupling between the Cu atoms being propagated along a zigzag line, lying in the crystal's bc plane and connecting the Cu atoms through the N atoms. Furthermore, we report the calculated positions of the H atoms that have not been provided in experimental papers.

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3 Acta Physica Polonica A

2 2014

1 2011

3 Wdowik U.

2 Legut D.

1 Błachowski A.

1 Sýkora R.

Mechanical Properties of Tetragonal and Orthorhombic Phases of Quasi-One-Dimensional Antiferromagnet KCuF_{3}

Impurity Effect on Charge and Spin Density in α-Fe - Comparison between Cellular Model, Ab Initio Calculations and Experiment

Exchange Interactions in a Low-Dimensional Magnetic System Cu(H_{2}O)_{2}(en)SO_{4}