Coexistence of long-ranged magnetic order and superconductivity in the pnictide superconductor<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>SmFeAsO</mml:mtext></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mtext>F</mml:mtext><mml:mi>x</mml:mi></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mrow><mml:mo

Ryan, D. H.; Cadogan, J. M.; Ritter, C.; Canepa, F.; Palenzona, A.; Putti, M.

doi:10.1103/physrevb.80.220503

Cited by 42 publications

(56 citation statements)

References 26 publications

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“…As clearly seen, the magnetization shows a sharp jump at 35 T at T = 0.6 K (θ is kept at nearly zero degrees during these measurements) saturating at a value of only ∼ 0.06(2) µ B per formula unit (f.u.). This value is rather small, when compared to the estimates for the full Sm magnetic moment of 0.4 − 0.6 µ B reported in the literature, 12,14 suggesting that only a partial reorientation of the magnetic moments is observed at H max 35 T. These results indicate that much higher fields are required to fully suppress the antiferromagnetic order. Notice that no additional jumps in the c-axis component of the magnetization are observed at base temperature and under fields up to 60 T, see Fig.…”

Section: Magnetic Fieldmentioning

confidence: 50%

Rearrangement of the antiferromagnetic ordering at high magnetic fields in SmFeAsO and SmFeAsO0.9F0.1
Moll
¹
,
Puźniak
²
,
Ninios
³

et al. 2011
Phys. Rev. B
19
1
12
0
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The low-temperature antiferromagnetic state of the Sm-ions in both nonsuperconducting SmFeAsO and superconducting SmFeAsO0.9F0.1 single crystals was studied by magnetic torque, magnetization, and magnetoresistance measurements in magnetic fields up to 60 T and temperatures down to 0.6 K. We uncover in both compounds a distinct rearrangement of the antiferromagnetically ordered Sm-moments near 35 − 40 T. This is seen in both, static and pulsed magnetic fields, as a sharp change in the sign of the magnetic torque, which is sensitive to the magnetic anisotropy and hence to the magnetic moment in the ab-plane, (i.e. the FeAs-layers), and as a jump in the magnetization for magnetic fields perpendicular to the conducting planes. This rearrangement of magnetic ordering in 35 − 40 T is essentially temperature independent and points towards a canted or a partially polarized magnetic state in high magnetic fields. However, the observed value for the saturation moment above this rearrangement, suggests that the complete suppression of the antiferromagnetism related to the Sm-moments would require fields in excess of 60 T. Such a large field value is particularly remarkable when compared to the relatively small Néel temperature TN 5 K, suggesting very anisotropic magnetic exchange couplings. At the transition, magnetoresistivity measurements show a crossover from positive to negative field-dependence, indicating that the charge carriers in the FeAs planes are sensitive to the magnetic configuration of the rare-earth elements. This is indicates a finite magnetic/electronic coupling between the SmO and the FeAs layers which are likely to mediate the exchange interactions leading to the long range antiferromagnetic order of the Sm ions.

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Section: Magnetic Fieldmentioning

confidence: 50%

Rearrangement of the antiferromagnetic ordering at high magnetic fields in SmFeAsO and SmFeAsO0.9F0.1
Moll
¹
,
Puźniak
²
,
Ninios
³

et al. 2011
Phys. Rev. B
19
1
12
0
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“…4), reminiscent of the low-temperature ordering of the Sm moments in SmFeAsO. 31,32 No Fe moment is observed within the limits of the experiment. At 5 K, the ordered magnetic moment of the Np ions is 1.70 ± 0.07μ B , in excellent agreement with Mössbauer spectroscopy estimations.…”

Section: Resultsmentioning

confidence: 73%

Negative thermal expansion and antiferromagnetism in the actinide oxypnictide NpFeAsO

Klimczuk

Walker²,

Springell³

et al. 2012

Phys. Rev. B

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A neptunium analog of the LaFeAsO tetragonal layered compound has been synthesized and characterized by a variety of experimental techniques. The occurrence of long-range magnetic order below a critical temperature T N = 57 K is suggested by anomalies in the temperature-dependent magnetic susceptibility, electrical resistivity, Hall coefficient, and specific-heat curves. Below T N , powder neutron diffraction measurements reveal an antiferromagnetic structure of the Np sublattice, with an ordered magnetic moment of 1.70 ± 0.07μ B aligned along the crystallographic c axis. No magnetic order has been observed on the Fe sublattice, setting an upper limit of about 0.3μ B for the ordered magnetic moment on the iron. High-resolution x-ray powder diffraction measurements exclude the occurrence of lattice transformations down to 5 K, in sharp contrast to the observation of a tetragonal-to-orthorhombic distortion in the rare-earth analogs, which has been associated with the stabilization of a spin-density wave on the iron sublattice. Instead, a significant expansion of the NpFeAsO lattice parameters is observed with decreasing temperature below T N , corresponding to a relative volume change of about 0.2% and to an Invar behavior between 5 and 20 K. First-principles electronic structure calculations based on the local spin density plus Coulomb interaction and the local density plus Hubbard-I approximations provide results in good agreement with the experimental findings.

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“…In contrast to the Fe 1+y (Te 1−x Se x ) family, 13,14 all neutron diffraction measurements to date indicate that the AFM order in the doped ROFeAs (R = rare earth) and AEFe 2 As 2 families is commensurate, 4,[15][16][17][18][19][20][21][22][23] and characterized by the so-called "stripe-like" magnetic structure. 13,14 Nevertheless, other measurements employing local probes of magnetism, such as 75 As nuclear magnetic resonance (NMR), 24 muon spin relaxation (µSR), 25 and 57 Fe Mössbauer spectroscopy 26 have proposed that the magnetic order is, in fact, incommensurate for the doped compounds.…”

mentioning

confidence: 99%

Commensurate antiferromagnetic ordering inBa(Fe1−xCox)2
Kim
¹
,
Kreyßig
²
,
Lee
³

et al. 2010
Phys. Rev. B
21
4
18
0
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We describe x-ray resonant magnetic diffraction measurements at the Fe K-edge of both the parent BaFe2As2 and superconducting Ba(Fe0.953Co0.047)2As2 compounds. From these high-resolution measurements we conclude that the magnetic structure is commensurate for both compositions. The energy spectrum of the resonant scattering is in reasonable agreement with theoretical calculations using the full-potential linear augmented plane wave method with a local density functional. PACS numbers: 74.70.Xa, 74.25.Dw The observation of coexistence and competition between superconductivity (SC) and antiferromagnetic (AFM) order in some members of the iron arsenide family of superconductors has raised interesting issues regarding the nature of both the SC and AFM states. Several theoretical treatments have demonstrated that coexistence is inconsistent with conventional BCS coupling, whereas the s ± state, arising from pairing through magnetic fluctuations, is compatible with coexistence and competition between SC and AFM order. [1][2][3][4][5] However, the nature of the AFM state in the doped superconducting compounds, particularly the potential for incommensurabilty of the magnetic structure, remains a significant issue under debate in both theoretical and experimental work.It has been argued that an incommensurate magnetic structure is expected for the doped iron arsenides because of imperfect nesting of the hole and electron Fermi surface pockets, 6,7 referencing previous work on chromium.8 Some theoretical models find that the coexistence between AFM and SC points to incommensurate AFM order. 6,7,9 However, it has also been noted that while incommensurability may broaden the coexistence regime, 10 it does not appear to be a prerequisite for coexistence.5 Recent calculations 11 of the spin susceptibility in the parent and doped AEFe 2 As 2 (AE = Ca, Ba, Sr) compounds point to incommensurability as the origin of the anisotropy observed in the low-energy spin fluctuation spectrum of Ba(Fe 0.926 Co 0.074 ) 2 As 2 . 12In contrast to the Fe 1+y (Te 1−x Se x ) family, 13,14 all neutron diffraction measurements to date indicate that the AFM order in the doped ROFeAs (R = rare earth) and AEFe 2 As 2 families is commensurate, 4,15-23 and characterized by the so-called "stripe-like" magnetic structure.13,14 Nevertheless, other measurements employing local probes of magnetism, such as 75 As nuclear magnetic resonance (NMR), 24 muon spin relaxation (µSR), 25 and 57 Fe Mössbauer spectroscopy 26 have proposed that the magnetic order is, in fact, incommensurate for the doped compounds. Zero-field µSR measurements on doped LaFeAs(O 0.97 F 0.03 ) noted a much faster damping of the signal than found for the undoped parent compound and attributed this to incommensurate AFM order.25 Supporting this view, NMR measurements 24,27 on underdoped Ba(Fe 1−x Co x ) 2 As 2 (x = 0.02, 0.04) 27 and (x = 0.06) 24 found a strong broadening of the 75 As lines attributable to the appearance of a distribution of internal fields at low temperatures in the m...

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Coexistence of long-ranged magnetic order and superconductivity in the pnictide superconductorSmFeAsO1−xFx

Cited by 42 publications

References 26 publications

Rearrangement of the antiferromagnetic ordering at high magnetic fields in SmFeAsO and SmFeAsO0.9F0.1
Moll
¹
,
Puźniak
²
,
Ninios
³

et al. 2011
Phys. Rev. B
19
1
12
0
View full text Add to dashboard Cite

Rearrangement of the antiferromagnetic ordering at high magnetic fields in SmFeAsO and SmFeAsO0.9F0.1
Moll
¹
,
Puźniak
²
,
Ninios
³

et al. 2011
Phys. Rev. B
19
1
12
0
View full text Add to dashboard Cite

Negative thermal expansion and antiferromagnetism in the actinide oxypnictide NpFeAsO

Commensurate antiferromagnetic ordering inBa(Fe1−xCox)2
Kim
¹
,
Kreyßig
²
,
Lee
³

et al. 2010
Phys. Rev. B
21
4
18
0
View full text Add to dashboard Cite

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Coexistence of long-ranged magnetic order and superconductivity in the pnictide superconductorSmFeAsO1−xFx

Cited by 42 publications

References 26 publications

Rearrangement of the antiferromagnetic ordering at high magnetic fields in SmFeAsO and SmFeAsO0.9F0.1Moll1, Puźniak2, Ninios3 et al. 2011Phys. Rev. B191120View full textAdd to dashboardCite

Rearrangement of the antiferromagnetic ordering at high magnetic fields in SmFeAsO and SmFeAsO0.9F0.1Moll1, Puźniak2, Ninios3 et al. 2011Phys. Rev. B191120View full textAdd to dashboardCite

Negative thermal expansion and antiferromagnetism in the actinide oxypnictide NpFeAsO

Commensurate antiferromagnetic ordering inBa(Fe1−xCox)2Kim1, Kreyßig2, Lee3 et al. 2010Phys. Rev. B214180View full textAdd to dashboardCite

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Rearrangement of the antiferromagnetic ordering at high magnetic fields in SmFeAsO and SmFeAsO0.9F0.1
Moll
¹
,
Puźniak
²
,
Ninios
³

et al. 2011
Phys. Rev. B
19
1
12
0
View full text Add to dashboard Cite

Rearrangement of the antiferromagnetic ordering at high magnetic fields in SmFeAsO and SmFeAsO0.9F0.1
Moll
¹
,
Puźniak
²
,
Ninios
³

et al. 2011
Phys. Rev. B
19
1
12
0
View full text Add to dashboard Cite

Commensurate antiferromagnetic ordering inBa(Fe1−xCox)2
Kim
¹
,
Kreyßig
²
,
Lee
³

et al. 2010
Phys. Rev. B
21
4
18
0
View full text Add to dashboard Cite