Versatile fluoride substrates for Fe-based superconducting thin films

Kurth, F.; Reich, Elke; Hänisch, Jens; Ichinose, Ataru; Tsukada, I.; Hühne, Ruben; Trommler, Sascha; Engelmann, Jan; Schultz, L.; Holzäpfel, B.; Iida, K.

doi:10.1063/1.4801312

Cited by 51 publications

(67 citation statements)

References 29 publications

(31 reference statements)

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“…The in-plane lattice parameter of Co-doped Ba122 film on CaF 2 is smaller than those of Co-doped Ba122 bulk samples [61,62], which indicates that the film received the in-plane compressive strain. The obtained superconducting transition temperature is T onset c ≈ 28 K [63], which is higher than the highest T c in Co-doped Ba122 bulk samples [61,62].…”

Section: -Systemmentioning

confidence: 94%

“…However, in thin films of 1111, 122, and 11, the highest T c is commonly obtained in the case of CaF 2 substrates. Tsukada et al firstly reported the effectiveness of the CaF 2 substrate in the 11 film fabrication [40], and then the fabrication of the film with high T c were reported in other systems [31,41,63]. Here, we define the lattice misfit,…”

Section: Substrate Materials In the Films Fabrication Of Iron-based Smentioning

confidence: 99%

“…We use the values reported in refs. [27,63,168,169] as a bulk , and the values of a sub , which are summarized in Table 1. In Figure 1, we plot the lattice constants and T c for films as a function of M. In a simple way, the positive (negative) M is expected to result in the tensile (compressive) strain.…”

Section: Substrate Materials In the Films Fabrication Of Iron-based Smentioning

confidence: 99%

“…The reason why the behaviors in the BaF 2 and SrF 2 substrates with large α 300K are different from the above expectations may be that the lattice mismatches in these two substrates are too large. Dependence of lattice parameters and T c for NdFeAs(O,F) films [189], SmFeAs(O,F) films [190], Ba(Fe 1−x Co x ) 2 As 2 films [51,63], and FeSe 0.5 Te 0.5 films [40,52,191] on the coefficient of thermal expansion at 300 K, α 300K .…”

Section: Substrate Materials In the Films Fabrication Of Iron-based Smentioning

confidence: 99%

“…These studies were performed for obtaining the high J c or fabricating junctions and devices, and there were no reports on the growth of Co-doped Ba122 films on oxide substrates with T c higher than ∼26 K which was the highest T c of Co-doped Ba122 bulk samples [61,62]. Iida et al fabricated the Co-doped Ba122 films on fluoride AEF 2 (AE = Ca, Sr, Ba) substrates [63], which had been used in the film growth of 11- [40] and 1111-systems [38]. The in-plane lattice parameter of Co-doped Ba122 film on CaF 2 is smaller than those of Co-doped Ba122 bulk samples [61,62], which indicates that the film received the in-plane compressive strain.…”

Section: -Systemmentioning

confidence: 99%

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Comparative Review on Thin Film Growth of Iron-Based Superconductors

2017

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Abstract:Since the discovery of the novel iron-based superconductors, both theoretical and experimental studies have been performed intensively. Because iron-based superconductors have a smaller anisotropy than high-T c cuprates and a high superconducting transition temperature, there have been a lot of researchers working on the film fabrication of iron-based superconductors and their application. Accordingly, many novel features have been reported in the films of iron-based superconductors, for example, the fabrication of the epitaxial film with a higher T c than bulk samples, the extraction of the metastable phase which cannot be obtained by the conventional solid state reaction, and so on. In this paper, we review the progress of research on thin film fabrications of iron-based superconductors, especially the four categories: LnFeAs(O,F) (Ln = Lanthanide), AEFe 2 As 2 (AE = Alkaline-earth metal), FeCh (Ch = Chalcogen), and FeSe monolayer. Furthermore, we focus on two important topics in thin films of iron-based superconductors; one is the substrate material for thin film growth on the iron-based superconductors, and the other is the whole phase diagram in FeSe 1−x Te x which can be obtained only by using film-fabrication technique.

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Section: -Systemmentioning

confidence: 94%

Section: Substrate Materials In the Films Fabrication Of Iron-based Smentioning

confidence: 99%

Section: Substrate Materials In the Films Fabrication Of Iron-based Smentioning

confidence: 99%

Section: Substrate Materials In the Films Fabrication Of Iron-based Smentioning

confidence: 99%

Section: -Systemmentioning

confidence: 99%

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Comparative Review on Thin Film Growth of Iron-Based Superconductors

2017

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Resistivity in Ba(FeCo)As: Comparison of thin films and single crystals

Ummarino

Galasso

Pecchio

et al. 2015

Physica Status Solidi (b)

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The temperature dependence of the resistivity of epitaxial Ba(Fe1−xCox)2As2 thin films (with nominal doping x=0.08,0.1 and 0.15) has been analysed and compared with analogous measurements on single crystals taken from literature. The ρfalse(Tfalse) of thin films looks different from that of single crystals, even when the cobalt content is the same. All ρfalse(Tfalse) curves can be fitted by considering an effective two‐band model (with holes and electrons bands) in which the electrons are more strongly coupled with the bosons (spin fluctuations) than holes, while the effect of impurities is mainly concentrated in the hole band. Within this model the mediating boson has the same characteristic energy in single crystals and thin films, but the shape of the transport spectral function at low energy has to be very different, leading to a “hardening” of the electron–boson spectral function in thin films, associated with the strain induced by the substrate.

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Excess currents in planar Ba(FeCo)As/TiO/Pb Josephson junctions

Döring

Reifert

Hasan

et al. 2015

Physica Status Solidi (b)

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We prepared planar hybrid Josephson junctions using Co‐doped BaFe2As2 thin films and polished single crystals as base electrode, sputtered, and subsequently oxidized titanium layers as barrier and a counter electrode from evaporated lead. On all junctions, RCSJ‐like current–voltage characteristics could be observed. The obtained IcRn products at 4.2 K range up to 95μV for thin film junctions and up to 1.15 mV for junctions on single crystals. For most of the junctions, an excess current with variable contribution to the total current could be observed. Unusual temperature dependencies are discussed for the critical and the excess currents, respectively. Investigations of the junctions under microwave irradiation were performed, therein Shapiro steps up to high orders and very clear modulations of the steps could be observed. Additionally, the origin of the excess current is discussed with respect to the microwave dependence. Furthermore, instead of a single junction, a network‐like modulation behavior of the critical current in magnetic fields was observed.

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Versatile fluoride substrates for Fe-based superconducting thin films

Cited by 51 publications

References 29 publications

Comparative Review on Thin Film Growth of Iron-Based Superconductors

Comparative Review on Thin Film Growth of Iron-Based Superconductors

Resistivity in Ba(FeCo)As: Comparison of thin films and single crystals

Excess currents in planar Ba(FeCo)As/TiO/Pb Josephson junctions

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