Mössbauer spectroscopy measurements on the 35.5 K superconductor<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Rb</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>δ</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi>EuFe</mml:mi><mml:mn>4</mml:mn></mml:msub><mml:msub><mml:mi>As</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>

Albedah, Mohammed A.; Nejadsattari, Farshad; Stadnik, Z. M.; Liu, Yi; Cao, Guanghan

doi:10.1103/physrevb.97.144426

Cited by 31 publications

(35 citation statements)

References 44 publications

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“…The large ordered moment of ∼ 6.5 µ B per formula unit is consistent with magnetism deriving from Eu 2+ ions 3 . Mössbauer spectroscopy measurements confirm that the magnetism derives from Eu 2+ moments (which orient perpendicular to the crystallographic c-axis), and indicate that there is no magnetic order of Fe moments down to at least 2 K 5,6 . A recent pre-print concluded that the Eu magnetism is quasi-2D in nature with strong magnetic fluctuation effects 7 .…”

Section: Introductionmentioning

confidence: 78%

Superconducting and magnetic phase diagram of RbEuFe4As4 and CsEuFe4As4 at high pressure

Jackson

VanGennep

et al. 2018

Phys. Rev. B

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The recently discovered (Rb,Cs)EuFe 4 As 4 compounds exhibit an unusual combination of superconductivity (T c ∼ 35 K) and ferromagnetism (T m ∼ 15 K). We have performed a series of x-ray diffraction, ac magnetic susceptibility, dc magnetization, and electrical resistivity measurements on both RbEuFe 4 As 4 and CsEuFe 4 As 4 to pressures as high as ∼ 30 GPa. We find that the superconductivity onset is suppressed monotonically by pressure while the magnetic transition is enhanced at initial rates of dT m /dP ∼ 1.7 K/GPa and 1.5 K/GPa for RbEuFe 4 As 4 and CsEuFe 4 As 4 respectively. Near 7 GPa, T c onset and T m become comparable. At higher pressures, signatures of bulk superconductivity gradually disappear. Room temperature x-ray diffraction measurements suggest the onset of a transition from tetragonal (T) to a half collapsed-tetragonal (hcT) phase at ∼ 10 GPa (RbEuFe 4 As 4) and ∼ 12 GPa (CsEuFe 4 As 4). The ability to tune T c and T m into coincidence with relatively modest pressures highlights (Rb,Cs)EuFe 4 As 4 compounds as ideal systems to study the interplay of superconductivity and ferromagnetism.

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Section: Introductionmentioning

confidence: 78%

Superconducting and magnetic phase diagram of RbEuFe4As4 and CsEuFe4As4 at high pressure

Jackson

VanGennep

et al. 2018

Phys. Rev. B

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“…Polycrystalline Eu(Rb,Cs)Fe 4 As 4 compounds were first discovered in 2016 and were shown to be superconductors with T c ∼ 35 K and a magnetic transition temperature T M ∼ 15 K 2 . Different from the undoped EuFe 2 As 2 where Eu 2+ orders antiferromagnetically [9][10][11] , the magnetic transition in RbEuFe 4 As 4 is suggested to be ferromagnetic which is associated with the ordering of the Eu 2+ moments perpendicular to the crystallographic c axis 4,8 . Though the exact magnetic structure of EuRbFe 4 As 4 has not been established so far, the possible coexistence of superconductivity and ferromagnetism makes EuRbFe 4 As 4 one of the systems where the relation between these states may be studied [12][13][14][15][16][17][18][19][20][21][22][23][24] .…”

Section: Introductionmentioning

confidence: 99%

Pressure-temperature phase diagram of the EuRbFe4As4 superconductor

Bud’ko

Bao

et al. 2019

Phys. Rev. B

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The pressure dependencies of the magnetic and superconducting transitions, as well as that of the superconducting upper critical field are reported for single crystalline EuRbFe4As4. Resistance measurements were performed under hydrostatic pressures up to 6.21 GPa and in magnetic fields up to 9 T. Zero-field-cool magnetization measurements were performed under hydrostatic pressures up to 1.24 GPa under 20 mT applied field. Superconducting transition temperature, Tc, up to 6.21 GPa and magnetic transition temperature, TM, up to 1.24 GPa were obtained and a pressure-temperature phase diagram was constructed. Our results show that Tc is monotonically suppressed upon increasing pressure. TM is linearly increased up to 1.24 GPa. For the studied pressure range, no signs of the crossing of TM and Tc lines are observed. The normalized slope of the superconducting upper critical field is gradually suppressed with increasing pressure, which may be due to the continuous change of Fermi-velocity vF with pressure.

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“…For Eu(Fe0.86Ir0.14)2As2 superconductor with Tsc = 22.5 K and double reentrance at lower temperature, the Eu 2+ moments order magnetically at 18 K with an appreciable FM component and the Eu hyperfine field of 28.5 T at 4. It can be additionally noted that the FM order of Eu magnetic moments laying in the ab-plane was detected by 151 Eu Mössbauer measurements for superconducting AEuFe4As4 (A = Rb [36] and Cs [37]) with the europium hyperfine field of 22.5 T and 22.4 T, respectively. In this case, the sheets of Eu atoms are separated by the AFe4As4 unit which rules out the possibility of any strong interaction between the Eu planes.…”

Section: Resultsmentioning

confidence: 85%

“…Another examples of the Eu to Fe magnetic field transfer and the Eu canting are: Eu(Fe0.71Co0.29)2As2 with Bt = 1.27(2)T and  = 40(1) [8], or Eu(Fe0.75Ru0.25)2As2 with Bt = 0.71(2) T [35]. An interesting results of the Bt = 0.6 T were reported for the ferromagnetic superconductors AEuFe4As4 (A = Rb [36] and Cs [37]) with Eu moments laying in the ab-plane.…”

Section: Resultsmentioning

confidence: 92%

“…This effect may result in competition between magnetism and superconductivity in EuFe2As2-based superconductors, because the Zeeman effect, which arises due to the FM order, strongly disfavors formation of the Cooper pair. However, as shown for many EuFe2As2-based compounds, this does not prevent the occurrence of superconductivity [36,37,10]. Eventually, the reentrant effect in some cases was observed [19,20].…”

Section: Discussionmentioning

confidence: 92%

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57Fe and 151Eu Mössbauer Studies of 3d-4f Spin Interplay in EuFe2-xNixAs2

Komędera

Gatlik

Błachowski

et al. 2021

Preprint

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The EuFe2-xNixAs2 compounds exhibiting 3d and/or 4f magnetic order were investigated by means of 57Fe and 151Eu Mössbauer spectroscopy. Additionally, results for the end members of this system, i.e. EuFe2As2 and EuNi2As2, are reported for comparison. It was found that spin-density-wave order of the Fe itinerant moments is monotonically suppressed by Ni-substitution. However, the 3d magnetic order survives at the lowest temperature up to at least x = 0.12 and it is certainly completely suppressed for x = 0.20. The Eu localized moments order regardless of the Ni concentration, but undergo a spin reorientation with increasing x from the alignment parallel to the a-axis in the parent compound, toward c-axis alignment for x > 0.07. The change of the 4f spins ordering from antiferromagnetic to ferromagnetic takes place simultaneously with a disappearance of the 3d spins order what is the evidence of a strong coupling between magnetism of Eu2+ ions and the conduction electrons of [Fe2-xNixAs2]2- layers. The Fe nuclei experience the transferred hyperfine magnetic field due to the Eu2+ ordering for Ni-substituted samples with x > 0.04, while the transferred field is undetectable in EuFe2As2 and for compound with a low Ni-substitution level. It seems that the 4f ferromagnetic component arising from a tilt of the Eu2+ moments to the crystallographic c-axis leads to the transferred magnetic field at the Fe atoms. The superconductivity is not observed down to 1.8 K, although a comparison with 57Fe and 151Eu Mössbauer data for EuFe2As2-based superconductors indicates a similar magnetic structure.

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Mössbauer spectroscopy measurements on the 35.5 K superconductorRb1−δEuFe4As4

Cited by 31 publications

References 44 publications

Superconducting and magnetic phase diagram of RbEuFe4As4 and CsEuFe4As4 at high pressure

Superconducting and magnetic phase diagram of RbEuFe4As4 and CsEuFe4As4 at high pressure

Pressure-temperature phase diagram of the EuRbFe4As4 superconductor

57Fe and 151Eu Mössbauer Studies of 3d-4f Spin Interplay in EuFe2-xNixAs2

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Mössbauer spectroscopy measurements on the 35.5 K superconductorRb1−δEuFe4As4

Cited by 31 publications

References 44 publications

Superconducting and magnetic phase diagram of RbEuFe4As4 and CsEuFe4As4 at high pressure

Superconducting and magnetic phase diagram of RbEuFe4As4 and CsEuFe4As4 at high pressure

Pressure-temperature phase diagram of the EuRbFe4As4 superconductor

57Fe&nbsp;and 151Eu&nbsp;Mössbauer Studies of 3d-4f Spin Interplay in EuFe2-xNixAs2

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57Fe and 151Eu Mössbauer Studies of 3d-4f Spin Interplay in EuFe2-xNixAs2