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Title: Pressure-induced collapsed-tetragonal phase in SrCo 2 As 2

We present high-energy x-ray diffraction data under applied pressures up to p = 29GPa, neutron diffraction measurements up to p = 1.1GPa, and electrical resistance measurements up to p = 5.9GPa, on SrCo 2As 2. Our x-ray diffraction data demonstrate that there is a first-order transition between the tetragonal (T) and collapsed-tetragonal (cT) phases, with an onset above approximately 6 GPa at T = 7K. The pressure for the onset of the cT phase and the range of coexistence between the T and cT phases appears to be nearly temperature independent. The compressibility along the a axis is the same for the T and cT phases, whereas, along the c axis, the cT phase is significantly stiffer, which may be due to the formation of an As-As bond in the cT phase. Our resistivity measurements found no evidence of superconductivity in SrCo 2As 2 for p ≤ 5.9 GPa and T ≥ 1.8 K. The resistivity data also show signatures consistent with a pressure-induced phase transition for p ≳ 5.5 GPa. Single-crystal neutron diffraction measurements performed up to 1.1 GPa in the T phase found no evidence of stripe-type or A-type antiferromagnetic ordering down to 10 K. Spin-polarized total-energy calculationsmore » demonstrate that the cT phase is the stable phase at high pressure with a ca ratio of 2.54. As a result, these calculations indicate that the cT phase of SrCo 2As 2 should manifest either A-type antiferromagnetic or ferromagnetic order.« less
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  1. Iowa State Univ., Ames, IA (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 1098-0121; PRBMDO
Grant/Contract Number:
FG02-94ER14466; AC02-07CH11358; FG02-99ER45775; AC02-06CH11357; EAR1157758; EAR1128799; NA0001974; AC05-00OR22725
Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 92; Journal Issue: 22; Journal ID: ISSN 1098-0121
American Physical Society (APS)
Research Org:
Ames Lab., Ames, IA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1228422; OSTI ID: 1334455