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Distinct high-T transitions in underdoped Ba(1-x)KxFe2As2
R R Urbano1, E L Green, W G Moulton
1National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306-4005, USA.
Physical Review Letters
|September 28, 2010
Summary
In underdoped Ba0.84K0.16Fe2As2, distinct structural and antiferromagnetic transitions were observed, challenging previous findings of simultaneous transitions. Superconductivity coexists with antiferromagnetism in the orthorhombic phase.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Solid State Chemistry
Background:
- Iron-arsenide superconductors exhibit complex phase transitions.
- Understanding the relationship between structural, magnetic, and superconducting phases is crucial for elucidating superconductivity mechanisms.
Purpose of the Study:
- To resolve the discrepancy regarding the nature of phase transitions in underdoped Ba(0.84)K(0.16)Fe2As2.
- To precisely determine the transition temperatures and their correlation.
Main Methods:
- Detailed investigation using NMR spectroscopy.
- Analysis of single-crystal Ba(0.84)K(0.16)Fe2As2.
Main Results:
- The tetragonal-orthorhombic structural transition (T(S)≈110 K) is distinct from the antiferromagnetic transition (T(N)≈102 K).
- NMR experiments confirmed the first-order nature of the structural transition and the coexistence of phases.
- Superconductivity (T(c)=20 K) was found to develop in the orthorhombic phase and coexist with antiferromagnetism.
Conclusions:
- The structural and magnetic transitions in this underdoped iron arsenide are not simultaneous.
- This finding highlights similarities between hole-doped and electron-doped iron-arsenide superconductors.
- The observed phase relationships provide new insights into the interplay of magnetism and superconductivity.
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