Magnetic state effect upon the order-disorder phase transition in Fe-Co alloys: A first-principles study

Rahaman, Moshiour; Ruban, Andrei V.; Mookerjee, Abhijit; Johansson, Börje

doi:10.1103/physrevb.83.054202

Cited by 28 publications

(15 citation statements)

References 47 publications

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“…A similar conclusion has been derived in Ref. (), where the impact of the magnetic state on the ECIs has been studied in order to describe the ordering transition in Fe–Co alloys (see also Fig. ).…”

Section: Coupling Of Degrees Of Freedomsupporting

confidence: 76%

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Lambda transitions in materials science: Recent advances in CALPHAD and first‐principles modelling

Körmann

Breidi

Dudarev

et al. 2013

Physica Status Solidi (b)

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211 6792 465 This paper provides a comprehensive overview of state-ofthe-art computational techniques to thermodynamically model magnetic and chemical order-disorder transitions. Recent advances as well as limitations of various approaches to these so-called lambda transitions are examined in detail, focussing on calphad models and first-principles methods based on density functional theory (DFT). On the one hand empirical implementations -based on the Inden-Hillert-Jarl formalismare investigated, including a detailed interpretation of the relevant parameters, physical limiting cases and potential extensions. In addition, Bragg-Williams-based approaches as well as cluster-variation methods of chemical order-disorder transitions are discussed. On the other hand, it is shown how magnetic contributions can be introduced based on various microscopic model Hamiltonians (Hubbard model, Heisenberg model and beyond) in combination with DFT-computed parameters. As a result of the investigation we were able to indicate similarities between the treatment of chemical and magnetic degrees of freedom as well as the treatment within the calphad and DFT approaches. Potential synergy effects resulting from this overlap have been derived and alternative approaches have been suggested, in order to improve future thermodynamic modelling of lambda transitions.

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Section: Coupling Of Degrees Of Freedomsupporting

confidence: 76%

“…Even if the chemical order–disorder transition takes place below the magnetic transition, as for instance in FeCo and FeNi 3 , it turns out to be mandatory to account for the partial loss of magnetic long‐range order in the simulations . Based on the partial disordered local moment model (PDLM), Eckholm et al.…”

Section: Coupling Of Degrees Of Freedommentioning

confidence: 99%

Lambda transitions in materials science: Recent advances in CALPHAD and first‐principles modelling

Körmann

Breidi

Dudarev

et al. 2013

Physica Status Solidi (b)

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“…Actually it is certainly the presence of magnetic mo-ments on Co that matters, more than the type (ferromagnetic, antiferromagnetic) of long range order which is stabilized at low temperature. This is clear when using the disordered local moment (DLM) picture where local moments interact through effective pair interactions [7,10,44]. To summarize, from the analysis of our ab initio calculations within a simple tight-binding model, we have shown that order in CoPt alloys, in particular at the equiatomic concentration, is principally driven by magnetic effects.…”

mentioning

confidence: 76%

Magnetism: the driving force of order in CoPt, a first-principles study

Karoui¹,

Amara²,

Legrand³

et al. 2013

J. Phys.: Condens. Matter

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CoPt equiatomic alloy orders according to the tetragonal L1(0) structure which favors strong magnetic anisotropy. Conversely, magnetism can influence the chemical ordering. We present here ab initio calculations of the stability of the L1(0) and L1(2) structures of Co-Pt alloys in their paramagnetic and ferromagnetic states. They show that magnetism strongly reinforces the ordering tendencies in this system. A simple tight-binding analysis allows us to account for this behavior in terms of some pertinent parameters.

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“…the CsCl-type ordering (the 2nd order phase transition) takes place at 600°C [16,17]. The Curie point for Fe 70 Co 30 coincides with the solid state phase transition at 950°C.…”

Section: Introductionmentioning

confidence: 90%