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Title: Structural and magnetic phase transitions near optimal superconductivity in BaFe 2(As 1-xP x) 2

In this study, we use nuclear magnetic resonance (NMR), high-resolution x-ray and neutron scattering to study structural and magnetic phase transitions in phosphorus-doped BaFe 2(As 1-xP x) 2. Thus, previous transport, NMR, specific heat, and magnetic penetration depth measurements have provided compelling evidence for the presence of a quantum critical point (QCP) near optimal superconductivity at x = 0.3. However, we show that the tetragonal-to-orthorhombic structural (T s) and paramagnetic to antiferromagnetic (AF, T N) transitions in BaFe 2(As 1-xP x) 2 are always coupled and approach to T N ≈ T s ≥ T c (≈ 29 K) for x = 0.29 before vanishing abruptly for x ≥ 0.3. These results suggest that AF order in BaFe 2(As 1-xP x) 2 disappears in a weakly first order fashion near optimal superconductivity, much like the electron-doped iron pnictides with an avoided QCP.
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [1] ;  [3] ;  [4] ;  [4] ;  [4] ;  [4] ;  [5] ;  [6] ;  [6] ;  [7] ;  [8] ;  [9] ;  [9] ;  [10]
  1. Chinese Academy of Sciences (CAS), Beijing (China)
  2. Chinese Academy of Sciences (CAS), Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)
  3. Argonne National Lab. (ANL), Argonne, IL (United States)
  4. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
  5. Canadian Neutron Beam Centre, Chalk River, ON (Canada)
  6. Paul Scherrer Inst. (PSI), Villigen (Switzerland)
  7. Technische Univ. Munchen, Garching (Germany)
  8. Max-Planck-Institut fur Festkorperforschung, Stuttgart (Germany); Max Planck Society Outstation at the Forschungsneutronenquelle Heinz Maier-Leibnitz, Garching (Germany)
  9. Renmin Univ. of China, Beijing (China)
  10. Chinese Academy of Sciences (CAS), Beijing (China); Rice Univ., Houston, TX (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0031-9007; PRLTAO
Grant/Contract Number:
2012CB821400; 2011CBA00110; 2015CB921302; 11374011; 91221303; 11222433; 11374364; SPRP-B: XDB07020300; DMR1362219; C-1839; AC02-06CH11357; AC02-07CH11358
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 114; Journal Issue: 15; Journal ID: ISSN 0031-9007
American Physical Society (APS)
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
Country of Publication:
United States
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1180557