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Magnetism and superconductivity in antimony doped binary and ternary iron chalcogenide single crystals

Dona Cherian ,  Nagendra G M ,  Suja E. Saji 

Indian Institute of Science, Bangalore 560 012, India

Since the discovery of superconductivity in Fe based compounds numerous studies have been carried out to synthesize new materials which can give a better insight into the mechanisms involved. Though Fe pnictides and chalcogenides share many common properties, the influence of composition on magnetic, structural and superconducting properties make Fe(Se,Te) more distinct. The key parameters controlling the physical properties of Fe1+yTe1-xSex are excess Fe content(y) at the interstitial site and doping at the anion site. The parent compound Fe1+yTe shows a coupled magneto-structural transition (TN) which decouples to two well separated transitions for certain concentration of excess Fe (y) [1]. On doping with Se, superconductivity emerges with a maximum TC of 15 K for Fe1+yTe0.5Se0.5  [2]. Also application of external pressure changes the superconducting and magnetic properties of Fe1+yTe and Fe1+ySe [3]. Assuming that doping impart chemical pressure we have doped Sb (2 % and 5%) on Fe1+yTe and Fe1+ySe0.5Te0.5 while keeping y unchanged. Single crystals of Fe1+yTe1-xSbx(x= 0, 2%, 5%) and Fe1+yTe0.49Se0.49Sb0.02 were grown by modified horizontal Bridgman method. Growth parameters were optimized to obtain high quality single crystals. On doping Fe1+yTe with Sb, antiferromagnetic transition at TN = 64 K shift to lower temperature. It is interesting to note that in antimony doped sample also the transition is first order in nature .This indicate the presence of structural transition even after doping. However on 5% doping the first order nature is not preserved. This indicates the tendency to suppress structural transition with higher doping. Subsequently we doped the chalcogen site of Fe1+ySe0.5Te0.5 with Sb. The doped crystals preserve superconductivity even though superconducting transition (TC)  falls to slightly lower temperature with a concomitant reduction in superconducting volume fraction. Physical properties of different Fe chalcogenide crystals will be compared and discussed in detail.       


1.  S.Rößler et al. Phys. Rev. B, 84, 174506 (2011)

2. K -W Yeh et al., EPL , 84,37002 (2008)                                                          

3. S. Margadonna et al., Phys. Rev. B , 80, 064506 (2009)


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Related papers

Presentation: Oral at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, General Session 5, by Suja E. Saji
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17

Submitted: 2013-04-15 15:41
Revised:   2013-07-17 11:16