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arXiv · 1104.3176

Formation of Collapsed Tetragonal Phase in EuCo2As2 under High Pressure

Matthew Bishop·Walter Uhoya·Georgiy Tsoi·Yogesh K. Vohra·Athena S. Sefat·Brian C. Sales
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Abstract

The structural properties of EuCo2As2 have been studied up to 35 GPa, through the use of x-ray diffraction in a diamond anvil cell at a synchrotron source. At ambient conditions, EuCo2As2 (I4/mmm) has a tetragonal lattice structure with a bulk modulus of 48 +/-4 GPa. With the application of pressure, the a-axis exhibits negative compressibility with a concurrent sharp decrease in c-axis length. The anomalous compressibility of the a-axis continues until 4.7 GPa, at which point the structure undergoes a second-order phase transition to a collapsed tetragonal (CT) state with a bulk modulus of 111 +/- 2 GPa. We found a strong correlation between the ambient pressure volume of 122 parents of superconductors and the corresponding tetragonal to collapsed tetragonal phase transition pressures

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Matthew Bishop, Walter Uhoya, Georgiy Tsoi, Yogesh K. Vohra, Athena S. Sefat, Brian C. Sales. 2011-04-15. Formation of Collapsed Tetragonal Phase in EuCo2As2 under High Pressure. https://doi.org/10.1088/0953-8984%2F22%2F42%2F425701

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