Bulk and Single Crystal Growth Progress of Iron-Based Superconductors (FBS): 1111 and 1144

Abstract

The discovery of iron-based superconductors (FBS) and their superconducting properties has generated huge research interest and provided a very rich physics high Tc family for fundamental and experimental studies. The 1111 (REFeAsO, RE = Rare earth) and 1144 (AEAFe4As4, AE = Ca, Eu; A = K, Rb) families are the two most important families of FBS, which offer the high Tc of 58 K and 36 K with doping and without doping, respectively. Furthermore, the crystal growth of these families is not an easy process, and a lot of efforts have been reported in this direction. However, the preparation of high-quality and suitable-sized samples is still challenging. In this short review, we will summarize the growth of materials with their superconducting properties, especially polycrystals and single crystals, for the 1111 and 1144 families, and make a short comparison between them to understand the developmental issues.

Cometal Addition Effect on Superconducting Properties and Granular Behaviours of Polycrystalline FeSe0.5Te0.5

“…There are also reports of similar results for Ag-added MgB 2 [ 54 ] and Sn-added alternative FBS bulk samples [ 50 ]. High-pressure techniques such as high-pressure growth and high-pressure sintering can be used to further improve the J c and F p of these samples [ 2 , 56 ].…”

“…Iron-based superconductors (FBSs) have attracted significant attention owing to their relatively high superconducting transition temperature ( T c ) of 58 K [ 1 , 2 , 3 ]. In 2008, FBSs were discovered through F-doped LaOFeAs [ 3 ], and since then, more than 100 compounds have been reported belonging to this high- T c superconductor.…”

“…Several types of processes have been reported to enhance flux-pinning behaviours such as metal additions, chemical doping using different metallic and non-metallic phases, high-energy irradiation, and the admixing of nanoparticles [ 30 ]. Recent studies have shown that different metal additions may be an effective and feasible approach for enhancing the superconducting properties of FBSs by introducing additional pinning centres and comprehending the superconducting mechanism [ 2 , 6 , 30 , 31 , 32 , 33 ]. In high- T c cuprate superconductors, the critical current density J c of YBa 2 Cu 3 O y (YBCO) is enhanced by Ag addition [ 34 ].…”

“…In 2008, FBSs were discovered through F-doped LaOFeAs [3], and since then, more than 100 compounds have been reported belonging to this high-T c superconductor. On the basis of parent compound structures, these compounds can be categorized into 6-7 families [2,[4][5][6]: REOFeAs (1111) (RE = rare earth), AFe 2 As 2 (A = Ba, K, Ca) (122), FeSe x Te 1-x (11), CaKFe 4 As 4 (1144), and LiFeAs (111), the 11 family. FeSe belongs to the 11 family [7,8] and has the simplest crystal structure [9,10] in FBSs.…”

Probing Phosphorus Solubility and Its Effect on Critical Temperature (Tc) in the Helical Superconducting Magnet RbEuFe4As4–xPx

“…The discovery of layered, Eu-containing compounds of composition AEuFe 4 As 4 (A = Rb, Cs) (1144 compounds, for short) has introduced new members to the family of materials that display superconductivity coexisting with a three-dimensional long-range local moment magnetic order. − Eu 2+ ions carry a large, spin-only moment of 7 μ B and enter a long-range ordered state at T N = 15 K. The moments have an easy-plane anisotropy and order ferromagnetically within one Eu-plane and exhibit a helical stacking with a period of four c -axis lattice constants along the c -axis. , The superconducting transition occurs at T c ∼ 36.5–37.0 K. − , Next to EuFe 2 As 2 -derived materials and the family of (Li 1– x M x )­OH-intercalated FeSe (M = Fe, Mn, Co; T c = 43 K), , RbEuFe 4 As 4 has the highest T c of any magnetic superconductor. The Eu–Fe-based 1144 superconductors are unique because they simultaneously display two mutually antagonistic physical orders, high magnetic ordering, and superconductivity, implying sizable magnetic exchange interactions in the presence of strong superconducting pairing.…”