HfFeGa<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow /><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>and HfMnGa<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow /><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>: Transition-metal-based itinerant ferromagnets with low Curie temperatures

Marques, C.; Janssen, Y.; Kim, M.S.; Wu, Lijun; Chi, Songxue; Lynn, J. W.; Aronson, M. C.

doi:10.1103/physrevb.83.184435

Cited by 6 publications

(4 citation statements)

References 53 publications

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“…There are very few compounds where Mn moments are so strongly hybridized with the conduction electrons that a much reduced moment results from correlations. Examples of this rare class are metallic MnSi [16], YMn 2 [17], and HfMnGa 2 [18], where the electronic fluctuations are so strong that there is no definite moment or valence state. Here, the moment results from correlations in a fully delocalized electronic medium, and magnetic order ensues from a collective instability of the Fermi surface, either a ferromagnetic (FM) Stoner instability [19] or an antiferromagnetic (AFM) spin density wave [20].…”

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confidence: 99%

CaMn2Al10: Itinerant Mn magnetism on the verge of magnetic order

et al. 2015

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We report the discovery of CaMn2Al10, a metal with strong magnetic anisotropy and moderate electronic correlations. Magnetization measurements find a Curie-Weiss moment of 0.83 µB/Mn, significantly reduced from the Hund's rule value, and the magnetic entropy obtained from specific heat measurements is correspondingly small, only ≈ 9 % of Rln 2. These results imply that the Mn magnetism is highly itinerant, a conclusion supported by density functional theory calculations that find strong Mn-Al hybridization. Consistent with the layered nature of the crystal structure, the magnetic susceptibility χ is anisotropic below 20 K, with a maximum ratio of χ [010] /χ [001] ≈ 3.5. A strong power-law divergence χ(T ) ∼ T −1.2 below 20 K implies incipient ferromagnetic order, and an Arrott plot analysis of the magnetization suggests a vanishingly low Curie temperature TC ∼ 0. Our experiments indicate that CaMn2Al10 is a rare example of a Mn-based weak itinerant magnet that is poised on the verge of ferromagnetic order.

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confidence: 99%

CaMn2Al10: Itinerant Mn magnetism on the verge of magnetic order

et al. 2015

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“…When the onsite interactions are very strong and the hybridization weak, robust insulators like LaMnPO [41], CaMn 2 Sb 2 [46] and BaMn 2 As 2 [39,47,48] occur where nearly full Hund's rule moments are found. When the hybridization is strong as in metallic MnX (X = P, As, Sb, Bi) [49][50][51], Rb-doped BaMn 2 As 2 [52], MnSi [53], YMn 2 [54] and HfMnGa 2 [55], residual onsite interactions can induce a Mn moment within the correlated electron bands that can be substantially weaker than the Hund's rule values. Assuming that the bandwidth reflects only Mn-Mn hybridization, a Mn moment emerges from the band for a critical value of hybridization that occurs for Mn-Mn spacings near 2.5 Å, antiferromagnetism and growing Mn moments are found for intermediate values of Mn-Mn spacing between 2.5 − 2.8 Å, while fully localized moments and strong FM character are found for well separated Mn ions with Mn-Mn spacings larger than 2.9 Å [56].…”

Section: Discussionmentioning

confidence: 99%

Correlations and incipient antiferromagnetic order within the linear Mn chains of metallic Ti$_4$MnBi$_2$

Pandey,

Miao,

Klemm

et al. 2020

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We report measurements on Ti4MnBi2, where a crystal structure involving linear chains of Mn ions suggests one-dimensional magnetic character. The electrical resistivity is metallic, consistent with the results of electronic structure calculations that find a robust Fermi surface albeit with moderate electronic correlations. Curie-Weiss fit to the magnetic susceptibility finds that the Mn moments are in the low-spin S = 1/2 configuration. Neutron diffraction measurements detect weak antiferromagnetic order within the Mn chains, with further evidence for the small staggered moment coming from the entropy associated with the ordering peak in the specific heat as well as from the results of spin-polarized electronic structure calculations. The antiferromagnetic moments are apparently associated with the d x 2 −y 2 and dxy orbitals of Mn while the remaining Mn orbitals are delocalized. Strong quantum fluctuations, possibly related to an electronic instability that forms the Mn moment or to the one-dimensional character of Ti4MnBi2, nearly overcome magnetic order.

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“…In metals, the Mn moments can be weakly hybridized, leading to the pronounced magnetic character of systems like MnX (X = P,As,Sb,Bi) [6,7,8], MnB [9], and RMn 2 X 2 (R = La,Lu,Y; X = Si,Ge) [10,11]. There is another class of metallic compounds like MnSi [1], YMn 2 [12], and HfMnGa 2 [13], in which the electronic fluctuations are so strong and there is no definite moment (or valence state). Therefore, the current need is to investigate such Mn-based magnetic compounds on theoretical grounds in order to check their ability towards potential applications [14].…”

Section: Introductionmentioning

confidence: 99%

The Case of Itinerant Magnetism in CaMn$_{2}$Al$_{10}$: Self-Consistent Renormalisation (SCR) Theory Study

Devanarayanan¹,

Sharma²,

Patel³

et al. 2022

Preprint

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We have applied the powerful self-consistent renormalization theory of spin fluctuations for the system CaMn2Al10 discovered in 2015 and was conjectured to be an itinerant magnet. We have calculated the inverse static i.e., (paramagnetic) susceptibility and have compared it with the experimental data (Phys. Rev. B 92, 020413, 2015). The agreement is very good. We have calculated spin fluctuations at various temperatures and have also estimated the strength of the electronic correlation i.e., (I = 0.3136 eV) in the Hubbard Hamiltonian. Based on our quantitative explanation of the inverse static i.e., (paramagnetic) susceptibility data within the framework of SCR theory, we can decisively conclude CaMn2Al10 exhibits the phenomena of itinerant magnetism. Further, our DFT and DFT+U calculations corroborate the strong Mn-Al hybridization which is the key behind the itinerant magnetism in this system. Our estimated correlations strength will provide a foundation for further studies of itinerant magnetism in this system.

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HfFeGa2and HfMnGa2: Transition-metal-based itinerant ferromagnets with low Curie temperatures

Cited by 6 publications

References 53 publications

CaMn2Al10: Itinerant Mn magnetism on the verge of magnetic order

CaMn2Al10: Itinerant Mn magnetism on the verge of magnetic order

Correlations and incipient antiferromagnetic order within the linear Mn chains of metallic Ti$_4$MnBi$_2$

The Case of Itinerant Magnetism in CaMn$_{2}$Al$_{10}$: Self-Consistent Renormalisation (SCR) Theory Study

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