Coexistence of Half-Metallic Itinerant Ferromagnetism with Local-Moment Antiferromagnetism in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>Ba</mml:mi><mml:mn>0.60</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="bold">K</mml:mi><mml:mn>0.40</mml:mn></mml:msub><mml:msub><mml:mi>Mn</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>As</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>

Pandey, Abhishek; Ueland, B. G.; Yeninas, Steven; Kreyßig, A.; Sapkota, A.; Zhao, Yang; Helton, Joel S.; Lynn, J. W.; McQueeney, R. J.; Furukawa, Yuji; Goldman, A. I.; Johnston, D. C.

doi:10.1103/physrevlett.111.047001

Cited by 42 publications

(71 citation statements)

References 34 publications

(57 reference statements)

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“…In particular, the As-4p electrons, with a small fraction near E F , could be spin-polarized. Such a nontrivial scenario was recently found and demonstrated in Ba 1−x K x Mn 2 As 2 which shows weak FM for x >0.19 [58][59][60] . Here the DOS of As-4p also shows a maximum at E F (the inset of Fig.…”

Section: E Density-functional Calculationsmentioning

confidence: 72%

Physical properties and electronic structure ofSr2Cr3As2O2containingCrO2
Jiang
¹
,
Bao
²
,
Zhai
³

et al. 2015
Phys. Rev. B
30
7
53
0
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We report the physical properties and electronic structure calculations of a layered chromium oxypnictide, Sr2Cr3As2O2, which crystallizes in a Sr2Mn3As2O2-type structure containing both CrO2 planes and Cr2As2 layers. The newly synthesized material exhibits a metallic conduction with a dominant electron-magnon scattering. Magnetic and specific-heat measurements indicate at least two intrinsic magnetic transitions below room temperature. One is an antiferromagnetic transition at 291 K, probably associated with a spin ordering in the Cr2As2 layers. Another transition is broad, occurring at around 38 K, and possibly due to a short-range spin order in the CrO2 planes. Our first-principles calculations indicate predominant two-dimensional antiferromagnetic exchange couplings, and suggest a KG-type (i.e. K2NiF4 type for CrO2 planes and G type for Cr2As2 layers) magnetic structure, with reduced moments for both Cr sublattices. The corresponding electronic states near the Fermi energy are mostly contributed from Cr-3d orbitals which weakly (modestly) hybridize with the O-2p (As-4p) orbitals in the CrO2 (Cr2As2) layers. The bare bandstructure density of states at the Fermi level is only ∼1/4 of the experimental value derived from the lowtemperature specific-heat data, consistent with the remarkable electron-magnon coupling. The title compound is argued to be a possible candidate to host superconductivity.

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Section: E Density-functional Calculationsmentioning

confidence: 72%

Physical properties and electronic structure ofSr2Cr3As2O2containingCrO2
Jiang
¹
,
Bao
²
,
Zhai
³

et al. 2015
Phys. Rev. B
30
7
53
0
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“…This is not borne out, based on the weak suppression of T N and the ordered magnetic moment. In addition, it is surprising to find that weak ferromagnetism (FM) appears at higher hole concentrations (x ≥ 0.16) which coexists with long-range AFM order [12,21,22]. A strong x-ray magnetic circular dichroism (XMCD) signal was observed at the As K-edge which shows that ferromagnetic ordering originates in As 4p conduction bands [23].…”

Section: Introductionmentioning

confidence: 99%

Robust antiferromagnetic spin waves across the metal-insulator transition in hole-doped BaMn2As2

et al. 2017

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BaMn2As2 is an antiferromagnetic insulator where a metal-insulator transition occurs with hole doping via the substitution of Ba with K. The metal-insulator transition causes only a small suppression of the Néel temperature (TN) and the ordered moment, suggesting that doped holes interact weakly with the Mn spin system. Powder inelastic neutron scattering measurements were performed on three different powder samples of Ba1−xKxMn2As2 with x =0, 0.125 and 0.25 to study the effect of hole doping and metallization on the spin dynamics of these compounds. We compare the neutron intensities to a linear spin wave theory approximation to the J1 − J2 − Jc Heisenberg model. Hole doping is found to introduce only minor modifications to the exchange energies and spin gap. The changes observed in the exchange constants are consistent with the small drop of TN with doping. INTRODUCTIONThe parent compounds of unconventional superconductors are typically antiferromagnetic (AFM), although they may be initially metals (as in the iron pnictides [1]) or Mott insulators (as in the copper oxide superconductors [2]). In either case, chemical substitution is often employed to destabilize the AFM ordered state and give rise to a superconducting ground state over some composition range. For the iron arsenides, they are already metallic and adding charge carriers serves to modify the Fermi surface and destabilize nesting-driven spin-density wave AFM order, resulting in superconductivity. In BaFe 2 As 2 , electrons or holes can be added via chemical substitutions such as Ba(Fe 1−x M x ) 2 As 2 with M = Co or Ni [3][4][5][6][7][8][9] and Ba 1−x K x Fe 2 As 2 [10], respectively.On the other hand, the effect of chemical substitutions in the copper oxides, such as La 2 CuO 4 , are twofold. Since they are insulators, chemical substitutions (such as La 2−x Sr x CuO 4 ) must both metallize the system and disrupt long-range AFM order in order to make the conditions favorable for superconductivity. In other words, both a metal-insulator transition and suppression of AFM order are necessary for superconductivity to appear in the cuprates.In attempting to find some commonality between the arsenides and cuprates, we search for other compounds that bridge these two systems. One possible system is BaMn 2 As 2 which shares the same crystal structure as BaFe 2 As 2 . Similar to cuprates, BaMn 2 As 2 is a quasitwo-dimensional AFM insulator possessing a square lattice of magnetic moments that order into a G-type AFM (checkerboard) pattern [11]. Also similar to the cuprates, a metal-insulator transition can be induced in BaMn 2 As 2 by replacing small amounts (a few percent) of Ba with K which effectively adds hole carriers [12,13]. Unlike the cuprates, the moments on Mn are large (S ≈ 2 to 5/2). In conjunction with large magnetic interactions (with a Néel transition temperature of T N = 625 K) [11,14,15], both neutron diffraction [16] and 75 As nuclear magnetic resonance [17] find that long-range AFM ordering is robust with hole doping, even at K concentra...

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“…The character of the magnetic state in these materials, spin density wave (SDW) or more conventional local antiferromagnetism, has been explored and argued over as it has implications for the superconducting pairing mechanism [4]. Further fueling this interest is the discovery of the coexistence of itinerant ferromagnetism and local antiferromagnetism in the related material Ba 1−x K x Mn 2 As 2 [5]. More recently and, perhaps more unexpectedly, the titaniumbased pnictide oxide Ba 1−x Na x Ti 2 Sb 2 O was discovered to have density wave states, spin (SDW) and/or charge, that coexist with a low temperature superconducting state [6].…”

mentioning

confidence: 99%

Competing magnetic states, disorder, and the magnetic character ofFe3Ga4

Mendez

Ekuma

et al. 2015

Phys. Rev. B

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The physical properties of metamagnetic Fe3Ga4 single crystals are investigated to explore the sensitivity of the magnetic states to temperature, magnetic field, and sample history. The data reveal a moderate anisotropy in the magnetization and the metamagnetic critical field along with features in the specific heat at the magnetic transitions T1 = 68 K and T2 = 360 K. Both T1 and T2 are found to be sensitive to the annealing conditions of the crystals suggesting that disorder affects the competition between the ferromagnetic (FM) and antiferromagnetic (AFM) states. Resistivity measurements reveal metallic transport with a sharp anomaly associated with the transition at T2. The Hall effect is dominated by the anomalous contribution which rivals that of magnetic semiconductors in magnitude (−5µΩ cm at 2 T and 350 K) and undergoes a change of sign upon cooling into the low temperature FM state. The temperature and field dependence of the Hall effect indicate that the magnetism is likely to be highly itinerant in character and that a significant change in the electronic structure accompanies the magnetic transitions. We observe a contribution from the topological Hall effect in the AFM phase suggesting a non-coplanar contribution to the magnetism. Electronic structure calculations predict an AFM ground state with a wavevector parallel to the crystallographic c-axis preferred over the experimentally measured FM state by ≈ 50 meV per unit cell. However, supercell calculations with a small density of Fe-antisite defects introduced tend to stabilize the FM over the AFM state indicating that antisite defects may be the cause of the sensitivity to sample synthesis conditions. PACS numbers: 75.30. Kz, 75.50.Bb, 75.50.Ee, 75.30.Cr INTRODUCTIONMetallic antiferromagnets have received renewed attention over the past few years, in part, because the iron pnictide and chalcogenide families of superconductors are derived via chemical substitutions into metallic antiferromagnetic parent compounds [1][2][3]. The character of the magnetic state in these materials, spin density wave (SDW) or more conventional local antiferromagnetism, has been explored and argued over as it has implications for the superconducting pairing mechanism [4]. Further fueling this interest is the discovery of the coexistence of itinerant ferromagnetism and local antiferromagnetism in the related material Ba 1−x K x Mn 2 As 2 [5]. More recently and, perhaps more unexpectedly, the titaniumbased pnictide oxide Ba 1−x Na x Ti 2 Sb 2 O was discovered to have density wave states, spin (SDW) and/or charge, that coexist with a low temperature superconducting state [6]. This activity has built on a long history of exploration of antiferromagnets related to the cuprate superconductors as the interesting magnetic properties of these compounds are thought to be of central importance to their unconventional superconducting states [7]. The difficulty in separating out the important aspects of these complex materials has driven explorations of simpler antiferromagnetic me...

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Coexistence of Half-Metallic Itinerant Ferromagnetism with Local-Moment Antiferromagnetism inBa0.60K0.40Mn2As2

Cited by 42 publications

References 34 publications

Physical properties and electronic structure ofSr2Cr3As2O2containingCrO2
Jiang
¹
,
Bao
²
,
Zhai
³

et al. 2015
Phys. Rev. B
30
7
53
0
View full text Add to dashboard Cite

Physical properties and electronic structure ofSr2Cr3As2O2containingCrO2
Jiang
¹
,
Bao
²
,
Zhai
³

et al. 2015
Phys. Rev. B
30
7
53
0
View full text Add to dashboard Cite

Robust antiferromagnetic spin waves across the metal-insulator transition in hole-doped BaMn2As2

Competing magnetic states, disorder, and the magnetic character ofFe3Ga4

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Coexistence of Half-Metallic Itinerant Ferromagnetism with Local-Moment Antiferromagnetism inBa0.60K0.40Mn2As2

Cited by 42 publications

References 34 publications

Physical properties and electronic structure ofSr2Cr3As2O2containingCrO2Jiang1, Bao2, Zhai3 et al. 2015Phys. Rev. B307530View full textAdd to dashboardCite

Physical properties and electronic structure ofSr2Cr3As2O2containingCrO2Jiang1, Bao2, Zhai3 et al. 2015Phys. Rev. B307530View full textAdd to dashboardCite

Robust antiferromagnetic spin waves across the metal-insulator transition in hole-doped BaMn2As2

Competing magnetic states, disorder, and the magnetic character ofFe3Ga4

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Product

Resources

About

Physical properties and electronic structure ofSr2Cr3As2O2containingCrO2
Jiang
¹
,
Bao
²
,
Zhai
³

et al. 2015
Phys. Rev. B
30
7
53
0
View full text Add to dashboard Cite

Physical properties and electronic structure ofSr2Cr3As2O2containingCrO2
Jiang
¹
,
Bao
²
,
Zhai
³

et al. 2015
Phys. Rev. B
30
7
53
0
View full text Add to dashboard Cite