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Title: Expansion of the tetragonal magnetic phase with pressure in the iron arsenide superconductor Ba 1 - x K x Fe 2 As 2

In the temperature-concentration phase diagram of most iron-based superconductors, antiferromagnetic order is gradually suppressed to zero at a critical point, and a dome of superconductivity forms around that point. The nature of the magnetic phase and its fluctuations is of fundamental importance for elucidating the pairing mechanism. In Ba 1–xK xFe 2As 2 and Ba 1–xNa xFe 2As 2, it has recently become clear that the usual stripelike magnetic phase, of orthorhombic symmetry, gives way to a second magnetic phase, of tetragonal symmetry, near the critical point, in the range from x = 0.24 to x = 0.28 for Ba 1–xK xFe 2As 2. In a prior study, an unidentified phase was discovered for x < 0.24 but under applied pressure, whose onset was detected as a sharp anomaly in the resistivity. Here we report measurements of the electrical resistivity of Ba 1–xK xFe 2As 2 under applied hydrostatic pressures up to 2.75 GPa, for x = 0.22, 0.24, and 0.28. The critical pressure above which the unidentified phase appears is seen to decrease with increasing x and vanish at x = 0.24, thereby linking the pressure-induced phase to the tetragonal magnetic phase observed at ambient pressure. In the temperature-concentrationmore » phase diagram of Ba 1–xK xFe 2As 2, we find that pressure greatly expands the tetragonal magnetic phase, while the stripelike phase shrinks. As a result, this reveals that pressure may be a powerful tuning parameter with which to explore the interplay between magnetism and superconductivity in this material.« less
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1] ;  [6]
  1. Univ. de Sherbrooke, Sherbrooke, QC (Canada)
  2. Ames Lab., Ames, IA (United States)
  3. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
  4. Nanjing Univ., Nanjing (China)
  5. Nanjing Univ., Nanjing (China); Canadian Institute for Advanced Research, Toronto, ON (Canada)
  6. Univ. de Sherbrooke, Sherbrooke, QC (Canada); Canadian Institute for Advanced Research, Toronto, ON (Canada)
Publication Date:
Report Number(s):
Journal ID: ISSN 2469-9950; PRBMDO
Grant/Contract Number:
AC02-07CH11358; 2011CBA00100
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 93; Journal Issue: 14; Journal ID: ISSN 2469-9950
American Physical Society (APS)
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1245047