Search results

1

Theoretical Study of Substitution of Si for Ge in Mn_{5}Ge_{3}

100%

Siberchicot B., Henrion R., Toboła J.

Acta Physica Polonica A

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1997

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vol. 91

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issue 2

467-470

EN

The substitution of silicon for germanium in Mn_{5}Ge_{3} leads to a decrease in the magnetization for x < 0.7 and then to phase transition toward a non-collinear antiferromagnetic order for Mn_{5}Si_{3}. The magnetic properties of Mn_{5}Ge_{3} and Mn_{5}(Ge_{0.5}Si_{0.5})_{3} are analyzed by means of band structure calculations.

2

The Electronic Structure of the RMn_{2}Ge_{2} (R = Ca, Y, La, Ba) Antiferromagnets

100%

Toboła J., Malaman B., Venturini G.

Acta Physica Polonica A

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2000

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vol. 97

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issue 5

761-765

EN

The electronic structure of the tetragonal RMn_{2}Ge_{2} (R = Ca, Y, La, Ba) antiferromagnets is presented using the self-consistent Korringa-Kohn-Rostoker method. According to the neutron refinements, two types of collinear antiferromagnetic structure are taken into account: AF_{1} for YMn_{2}Ge_{2} and AF_{2} for the other compounds. The calculated magnetic moments on Mn: 2.17μ_{B} (YMn_{2}Ge_{2}), 2.84 μ_{B} (CaMn_{2}Ge_{2}), 2.95 μ_{B} (LaMn_{2}Ge_{2}), and 3.47 μ_{B} (BaMn_{2}Ge_{2}) remain in good agreement with the neutron data (in μ_{B}) 2.20, 2.67, 3.05, and 3.66, respectively. As seen on antiferromagnetic density of states, all systems are metallic, however BaMn_{2}Ge_{2} is found near semimetallic limit. The total energy Korringa-Kohn-Rostoker computations on CaMn_{2}Ge_{2}, performed in both antiferromagnetic phases, result in preferring of the AF _{2} structure.

3

^{119}Sn Hyperfine Fields in RMn_{6}Sn_{6} (R = Mg, Zr, Hf). Experimental and Theoretical Study

100%

Mazet T., Toboła J., Venturini G., Malaman B.

Acta Physica Polonica A

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2000

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vol. 97

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issue 5

737-740

EN

We performed both ^{119}Sn Möossbauer experiments and electronic structure calculations using the Korringa-Kohn-Rostoker method on the hexagonal RMn_{6}Sn_{6} (R = Mg, Zr, and Hf) compounds. According to previous neutron diffraction results two types of commensurate magnetic order are investigated: ferromagnetic for R = Mg and antiferromagnetic for R = Zr and Hf. From ^{119}Sn Möossbauer measurements, high transferred hyperfine fields on the tin nuclei are observed. The H_{hf} values are well supported by the Korringa-Kohn- Rostoker results. Moreover, the calculated μ_{Mn} are in good agreement with the neutron diffraction data. When observing the density of states, ZrMn_{6}Sn_{6} is found near semimetallic limit.

4

Superconductivity, Weak Itinerant Ferromagnetism and Electronic Band Structure of Y_9Co_7

88%

Kołodziejczyk A., Wiendlocha B., Zalecki R., Toboła J., Kaprzyk S.

Acta Physica Polonica A

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2007

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vol. 111

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issue 4

513-526

EN

The paper presents experimental results for the intermetallic compound Y_9Co_7 which is the first very weak itinerant ferromagnetic superconductor. The measurements of electrical resistivity, susceptibility, magnetization, specific heat, nuclear magnetic resonance, and other properties show the magnetic transition at T_C≈ 4.5 K and the onset of superconductivity at about T_S≈ 2.5 K, revealing the coexistence state within a temperature interval below T_S. A few of the results are shortly reviewed and discussed. We focus attention on our recent ultraviolet photoemission spectroscopy and their comparison with our band structure calculations. Interpretations are considered which take into account the characteristic structure of the compound and different possible types of magnetic ordering.

5

Magnetic and Transport Properties of (Fe_{1-x}Ni_{x})_{2}P in View of KKR-CPA Results

76%

Kaprzyk S., Nizioł S., Toboła J., Zach R., Bacmann M., Fruchart D., Wolfers P.

Acta Physica Polonica A

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1997

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vol. 91

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issue 2

475-478

EN

We present results of the electronic structure study for the solid solution (Fe_{1-x}Ni_{x})_{2}P (space group P6̅2m). The samples were synthesized for x=0.0 up to 0.15. From the electrical conductivity measurements on these materials, it was verified that resistivity increases with increasing temperature up to the Curie point T_{C} and changes the slope at T_{C} decreasing when temperature is raised above T_{C}. To get insight into the possible origin of such observations, we carried out the Korringa-Kohn-Rostoker-coherent potential approximation electronic structure calculations for (Fe_{1-x}Ni_{x})_{2}P in the range of concentration x=0.0 up to 1.0. It was found that alloying with Ni in Fe_{2} P causes vanishing of spin band splitting and non-rigid band behaving of electronic valence states near the Fermi level. The polarization factor for electrons at E_{F} changes in (Fe_{1-x}Ni_{x})_{2}P with increasing x, and interestingly, it reaches maximum at x=0.1, closely to the concentration (x=0.08), when the largest value of T_{C} and a kink in temperature dependent resistivity were detected.

6

Magnetoelastic Properties of MnRhAs_{1-x}p_{x} and Band Structure Results from KKR-CPA

76%

Zach R., Kaprzyk S., Nizioł S., Toboła J., Bacmann M., Fruchart D., Wolfers P.

Acta Physica Polonica A

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1997

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vol. 91

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issue 2

471-474

EN

The magnetoelastic phase transitions were observed in MnRhAs_{1-x}P_{x} system (space group P6̅2m) by X-ray measurements (80 K < T < 300 K). For x = 0.33 and x = 0.4 contents an abrupt change of both lattice parameters and of the elementary cell volume at the metamagnetic transition was detected. The Korringa-Kohn-Rostoker electronic structure calculations performed for MnRhP compound show significant variations of densities of states at the Fermi level, while changing lattice data. The Korringa-Kohn- Rostoker-coherent potential approximation studies of disordered MnRhAs_{1-x}P_{x} system (x=0.6, 0.8, 1.0) were done at the ferromagnetic region. From our calculations we observe moving of bands near E_{F}, while substituting with isoelectronic metalloid, likely as while changing the crystal data in MnRhP.

Refine search results

6 Acta Physica Polonica A

1 2007

2 2000

3 1997

6 Toboła J.

3 Kaprzyk S.

2 Bacmann M.

2 Fruchart D.

2 Malaman B.

2 Nizioł S.

2 Venturini G.

2 Wolfers P.

2 Zach R.

1 Henrion R.

1 Kołodziejczyk A.

1 Mazet T.

1 Siberchicot B.

1 Wiendlocha B.

1 Zalecki R.

Theoretical Study of Substitution of Si for Ge in Mn_{5}Ge_{3}

The Electronic Structure of the RMn_{2}Ge_{2} (R = Ca, Y, La, Ba) Antiferromagnets

^{119}Sn Hyperfine Fields in RMn_{6}Sn_{6} (R = Mg, Zr, Hf). Experimental and Theoretical Study

Superconductivity, Weak Itinerant Ferromagnetism and Electronic Band Structure of Y_9Co_7

Magnetic and Transport Properties of (Fe_{1-x}Ni_{x})_{2}P in View of KKR-CPA Results

Magnetoelastic Properties of MnRhAs_{1-x}p_{x} and Band Structure Results from KKR-CPA