Year: 2015
Type: article
Abstract: We present high-energy x-ray diffraction data under applied pressures up to $p=29\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$, neutron diffraction measurements up to $p=1.1\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$, and electrical resistance measurements up to $p=5.9\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$, on ${\mathrm{SrCo}}_{2}{\mathrm{As}}_{2}$. 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 $T=7\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. 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 ${\mathrm{SrCo}}_{2}{\mathrm{As}}_{2}$ for $p\ensuremath{\le}5.9$ GPa and $T\ensuremath{\ge}1.8$ K. The resistivity data also show signatures consistent with a pressure-induced phase transition for $p \ensuremath{\gtrsim}5.5$ 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 calculations demonstrate that the cT phase is the stable phase at high pressure with a $\frac{c}{a}$ ratio of 2.54. Furthermore, these calculations indicate that the cT phase of ${\mathrm{SrCo}}_{2}{\mathrm{As}}_{2}$ should manifest either A-type antiferromagnetic or ferromagnetic order.
Source: Physical Review B
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
Awards: G102163711, GeoSoilEnviroCARS: A National Resource for Earth, Planetary, Soil and Environmental Science Research at the APS, G107546177, G1286251239, G1313983767, G1418315740, G1504018559, GEOSOILENVIROCARS: A NATIONAL RESOURCE FOR EARTH, PLANETARY, SOIL AND ENVIRONMENTAL SCIENCE RESEARCH AT THE ADVANCED PHOTON SOURCE, G1664757510, G1866217153, G1996433053, G2025663771, G222768804, G2287611682, G2316606464, G2327333655, G2441759041, G249831736, G262962599, G285533474, G3075337988, G3318903820, GEO CARS: A NATIONAL RESOURCE FOR EARTH, PLANETARY AND ENVIRONMENTAL SCIENCE RESEARCH AT THE ADVANCED PHOTON SOURCE, G412961744, G4155429592, G426311843, G4446722937, HPACT AN INTEGRATED HIGH PRESSURE FACILITY AT THE ADVANCED PHOTON SOURCE, G4707123693, G486686280, G498139845, G513797252, G5387317844, G5648016710, G5959670421, G6848031779, G6918803902, G7048178833, G7275060768, HPCAT-AN INTEGRATED HIGH-PRESSURE FACILITY AT THE ADVANCED PHOTON SOURCE, G7583137537, HPACT AN INTEGRATED HIGH PRESSURE FACILITY AT THE ADVANCED PHOTON SOURCE, HPCAT-AN INTEGRATED HIGH-PRESSURE FACILITY AT THE ADVANCED PHOTON SOURCE, G8286507625, GEOSOILENVIROCARS: A NATIONAL RESOURCE FOR EARTH, PLANETARY, SOIL AND ENVIRONMENTAL SCIENCE RESEARCH AT THE ADVANCED PHOTON SOURCE, G969889393, GEO CARS: A NATIONAL RESOURCE FOR EARTH, PLANETARY AND ENVIRONMENTAL SCIENCE RESEARCH AT THE ADVANCED PHOTON SOURCE, G993149817
OpenAlex ID: W2192004389