Induced magnetic ordering in alloyed compounds based on Pauli paramagnet YCo2

Śniadecki, Z.; Werwiński, Mirosław; Szajek, A.; Rößler, U.; Idzikowski, B.

doi:10.1063/1.4866848

Cited by 16 publications

(6 citation statements)

References 16 publications

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“…Shift of the measured critical concentration can be explained as an effect of using the rapid quenching technique for synthesis of our alloys. This results in chemical and topological disorder being introduced, which leads to the formation of magnetically ordered state [28,29,31]. When starting from an exchange enhanced Pauli paramagnet YCo 2 , an introduction of structural disorder (or addition of other element) causes the formation of magnetically ordered clusters (spin-glass-type behavior) with non-zero magnetic moment on Co atoms.…”

Section: Experimental and Computational Detailsmentioning

confidence: 99%

“…Moreover, the DyFe 2 /YFe 2 magnetic thin films are reversible exchange-spring magnets [20,21] and the YCo 2 alloys with rare-earth elements R 1−x Y x Co 2 (R = Er, Gd) are considered as magnetocaloric materials for application in magnetic refrigerators [22,23]. Our previous experimental and theoretical investigations on the Y(Fe 1−x Co x ) 2 system covered such issues as: magnetic moments of Y(Fe 1−x Co x ) 2 [24,25], electronic structure of YCo 2 [26,27], effect of YCo 2 doping [28], magnetic percolation in Y(Fe 1−x Co x ) 2 [29], Curie temperature of Y(Fe 1−x Co x ) 2 [30], and structural disorder in YCo 2 [31].…”

Section: Introductionmentioning

confidence: 99%

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Electronic specific heat coefficient and magnetic properties of Y(Fe1−xCox)2 Laves phases: A combined experimental and first

et al. 2019

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We investigated experimentally and computationally the concentration dependence of electronic specific heat coefficient γ in Y(Fe 1−x Cox) 2 pseudobinary Laves phase system. The experimentally observed maximum in γ(x) around the magnetic phase transition was interpreted within the local density approximation (LDA) combined with the virtual crystal approximation (VCA). To explain the formation of the observed maximum, we analyzed theoretically the dependence of the magnetic energy, magnetic moments, densities of states, and Fermi surfaces on the Co concentration. Furthermore, we carried out the calculations of density of states at the Fermi level as a function of fixed spin moment. The calculated Co concentration at which γ takes the maximum value (x max-LDA-VCA = 0.91) stays in good agreement with the measured value (x max-expt = 0.925). We conclude that the observed maximum in γ(x) results from the presence of the sharp DOS peak in the vicinity of the Fermi level. FIG. 1. Crystal structure of the cubic MgCu 2 -type Laves phase.

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Section: Experimental and Computational Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electronic specific heat coefficient and magnetic properties of Y(Fe1−xCox)2 Laves phases: A combined experimental and first

et al. 2019

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“…However, the underestimation of γ is a recognized weakness of the DFT method, resulting from the neglect of spin fluctuations and manybody effects in low-energy excitations [73]. Moreover, the γ value of 22.2 mJ mol −1 K −2 calculated for YbFe 4 Al 8 is more than twice the value of 9.1 mJ mol −1 K −2 that we obtained for another compound containing lanthanides and 3d-metal (Y 0.9 Ti 0.1 Co 2 ) [74]. The difference is due to the absence of the 4f contribution in the latter case and the slightly higher filling of the 3d shell in Co than in Fe.…”

Section: Density Of States At the Fermi Level And Electronic Specific...mentioning

confidence: 54%

Electronic structure of YbFe$_4$Al$_8$ antiferromagnet: A combined X-ray photoelectron spectroscopy and first-principles study

Marciniak¹,

Chełkowska²,

Bajorek³

et al. 2021

Preprint

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Depending on their chemical composition, Yb compounds often exhibit different valence states.Here we investigate the valence state of YbFe 4 Al 8 using X-ray photoelectron spectroscopy (XPS) and first-principles calculations. The XPS valence band of YbFe 4 Al 8 consists of two contributions coming from divalent (Yb 2+ ) and trivalent (Yb 3+ ) configurations. The determined value of the valence at room temperature is 2.81. Divalent and trivalent contributions are also observed for core-level Yb 4d XPS spectra. We study several collinear antiferromagnetic models of YbFe 4 Al 8 from the first-principles and for comparison we also consider LuFe 4 Al 8 with a fully filled 4f shell. We predict that only Fe sublattices of YbFe 4 Al 8 carry significant magnetic moments and that the most stable magnetic configuration is AFM-C with antiparallel columns of magnetic moments. We also present a Mullliken electronic population analysis describing charge transfer both within and between atoms. In addition, we also study the effect of intra-atomic Coulomb U repulsion term applied for 4f orbitals on Yb valence and Fe magnetic moments.

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“…Our previous experimental and theoretical studies on the Y 1−x Gd x (Fe 1−y Co y ) 2 system have included such topics as: effect of YCo 2 doping [17], magnetocaloric effects in Y 1−x Gd x Co 2 [13], Curie temperature of Y(Fe 1−y Co y ) 2 [18], structural disorder in YCo 2 [19], and electronic specific heat coefficient of Y(Fe 1−y Co y ) 2 [20]. In this work we show the Curie temperatures determined from first principles for pseudo-binary Laves phases Y 1−x Gd x (Fe 1−y Co y ) 2 .…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo calculations of Curie temperatures of Y$_{1-x}$Gd$_x$(Fe$_{1-y}$Co$_y$)$_2$ pseudobinary system

Wasilewski,

Werwiński

2021

Preprint

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The close-packed AB 2 structures called Laves phases constitute the largest group of intermetallic compounds. In this paper we computationally investigated the pseudo-binary Laves phase system Y 1−x Gd x (Fe 1−y Co y ) 2 spanning between the YFe 2 , YCo 2 , GdFe 2 , and GdCo 2 vertices. While the vast majority of the Y 1−x Gd x (Fe 1−y Co y ) 2 phase diagram is the ferrimagnetic phase, YCo 2 along with a narrow range of concentrations around it is the paramagnetic phase. We presented results obtained by Monte Carlo simulations of the Heisenberg model with parameters derived from firstprinciples calculations. For calculations we used the Uppsala atomistic spin dynamics (UppASD) code together with the spin-polarized relativistic Korringa-Kohn-Rostoker (SPR-KKR) code. From first principles we calculated the magnetic moments and exchange integrals for the considered pseudo-binary system, together with spin-polarized densities of states for boundary compositions. Furthermore, we showed how the compensation point with the effective zero total moment depends on the concentration in the considered ferrimagnetic phases. However, the main result of our study was the determination of the Curie temperature dependence for the system Y 1−x Gd x (Fe 1−y Co y ) 2 . Except for the paramagnetic region around YCo 2 , the predicted temperatures were in good qualitative and quantitative agreement with experimental results, which confirmed the ability of the method to predict magnetic transition temperatures for systems containing up to three different magnetic elements (Fe, Co, and Gd) simultaneously. For the Y(Fe 1−y Co y ) 2 and Gd(Fe 1−y Co y ) 2 systems our calculations matched the experimentally-confirmed Slater-Pauling-like behavior of T C dependence on the Co concentration. For the Y 1−x Gd x Fe 2 system we obtained, also in agreement with the experiment, a linear dependence of T C on the Gd concentration. In addition, on the example of Y 0.8 Gd 0.2 Co 2 ferrimagnet, we showed the possibility of predicting the non-trivial behavior of the temperature dependence of magnetization, confirmed by comparison with previous measurement results.

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Induced magnetic ordering in alloyed compounds based on Pauli paramagnet YCo2

Cited by 16 publications

References 16 publications

Electronic specific heat coefficient and magnetic properties of Y(Fe1−xCox)2 Laves phases: A combined experimental and first

Electronic specific heat coefficient and magnetic properties of Y(Fe1−xCox)2 Laves phases: A combined experimental and first

Electronic structure of YbFe$_4$Al$_8$ antiferromagnet: A combined X-ray photoelectron spectroscopy and first-principles study

Monte Carlo calculations of Curie temperatures of Y$_{1-x}$Gd$_x$(Fe$_{1-y}$Co$_y$)$_2$ pseudobinary system

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