Expansion of the tetragonal magnetic phase with pressure in the iron arsenide superconductor ${\mathrm{Ba}}_{1-x}{\mathrm{K}}_x{\mathrm{Fe}}_2{\mathrm{As}}_2$

Journal Article · 01 April 2016 · Physical Review B

DOI: https://doi.org/10.1103/PhysRevB.93.144401 · OSTI ID:1337668

Hassinger, Elena ^[1]; Gredat, G. ^[1]; Valade, F. ^[1]; de Cotret, S. Rene ^[1]; Cyr-Choiniere, O. ^[1]; Juneau-Fecteau, A. ^[1]; Reid, J. -Ph. ^[1]; Kim, H. ^[2]; Tanatar, M. A. ^[2]; Prozorov, R. ^[3]; Shen, B. ^[4]; Wen, H. -H. ^[5]; Doiron-Leyraud, N. ^[1]; Taillefer, Louis ^[6]

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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)

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_xFe₂As₂ and Ba_1–xNa_xFe₂As₂, 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_xFe₂As₂. 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_xFe₂As₂ 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-concentration phase diagram of Ba_1–xK_xFe₂As₂, 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.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-07CH11358; 2011CBA00100
• OSTI ID: 1337668
• Alternate ID(s): OSTI ID: 1245047
• Report Number(s): IS-J-8986; PRBMDO
• Journal Information: Physical Review B, Vol. 93, Issue 14; ISSN 2469-9950
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English