Tuning the superconducting and magnetic properties ofFeySe0.25Te0.75by varying the iron content

Abstract

The superconducting and magnetic properties of Fe y Se 0.25 Te 0.75 single crystals ͑0.9Յ y Յ 1.1͒ were studied by means of x-ray diffraction, superconducting quantum interference device magnetometry, muon-spin rotation, and elastic neutron diffraction. The samples with y Ͻ 1 exhibit coexistence of bulk superconductivity and incommensurate magnetism. The magnetic order remains incommensurate for y Ն 1 but with increasing Fe content superconductivity is suppressed and the magnetic correlation length increases. The results show that the superconducting and the magnetic properties of the Fe y Se 1−x Te x can be tuned not only by varying the Se/Te ratio but also by changing the Fe content.

Muon spin rotation study of magnetism and superconductivity in Ba(Fe1−xCox)2Bernhard1, Wang2, Nuccio3 et al. 2012Phys. Rev. B5422871View full textAdd to dashboardCite

“…46,48,67 This superconductivity-induced paramagnetic shift of the TF-μSR line shape, which has also been consistently observed in the present optimally and overdoped single crystals (not shown), is most likely related to the superconductivity-induced enhancement of the low-energy spin fluctuations.…”

“…42), or more recently the iron arsenides 11,12,15,17,19,20,[43][44][45][46][47] and iron selenides. [48][49][50] The neutron diffraction experiments were performed at the thermal four-circle single-crystal diffractometer TRICS at the spallation neutron source SINQ at PSI. A pyrolytic 184509-2 graphite (PG-002) monochromator was used with neutron wavelength λ = 2.4Å.…”

Effects of Iodine Annealing on Fe1+yTe0.6Se0.4

“…However, the excess iron that is located at the interstitial site in the Te/Se layer [7] has strong magnetism and acts as pair a breaker and suppresses superconductivity [8,9]. Thus, the as-grown Fe 1+y Te 1-x Se x single crystals only show filamentary superconductivity [10,11].…”

Interplay of structure, magnetism, and superconductivity in Se substituted iron telluride with excess Fe

“…The temperature composition phase diagram exhibits three regions, as Se composition increased up to 50%: commensurate AFM order followed by a region where incommensurate AFM order and superconductivity coexist, and bulk superconductivity [19]. In Fe 1+y Se 0.25 Te 0.75 , for low concentrations of Fe (y <0), bulk superconductivity and incommensurate magnetic order coexist, whereas for y ≥ 0 bulk superconductivity is suppressed by strong incommensurate magnetic correlations [29]. On the other hand, Fe 1+y Te 1−x Se x with y in the range 0.02 -0.05 and x ≤ 0.075, undergoes a phase transition to an antiferromagnetically ordered phase with a monoclinic structure [11].…”

“…Also, for the composition x = 0.05 both commensurate and incommensurate magnetic order might be present. [11,19,[27][28][29]. These studies mainly investigated the samples with low amount of excess Fe.…”