Bulletin of the American Physical Society
APS March Meeting 2010
Volume 55, Number 2
Monday–Friday, March 15–19, 2010; Portland, Oregon
Session J39: Focus Session: Iron Based Superconductors: Properties and Pressure
11:15 AM–2:03 PM,
Tuesday, March 16, 2010
Sponsoring Units: DCMP DMP
Chair: M McGuire, Oak Ridge National Laboratory
Abstract ID: BAPS.2010.MAR.J39.4
Abstract: J39.00004 : Uniaxial Pressure Measurements on Single-Crystal CaFe$_2$As$_2$*
11:51 AM–12:03 PM
Preview Abstract Abstract
Sung Hyuk Song
(Ames Lab; Iowa State University)
Measurements of single crystal CaFe$_2$As$_2$ have uncovered a variety of phases spanning a large range of temperatures, which makes them an interesting and important material for sorting out competing influences on strongly correlated phases. Uniaxial pressure measurements give insight into the role of dimensionality and hybridization. We apply uniaxial c-axis pressure to a single-crystal sample of CaFe$_2$As$_2$, mounted between stainless steel pressure spacers within an ac susceptibility coil. This setup is located at the base of an Oxford dilution refrigerator modified specifically for uniaxial pressure measurements. We find that a very small applied pressure, less than 0.1 kbar, induces a superconducting phase near 7K, with a transition temperature that varies little as pressure is increased further. We also find a second, strongly pressure-dependent transition near 3K. This transition temperature reaches a maximum at a pressure slightly over 1 kbar. These measurements demonstrate the sensitivity of CaFe$_2$As$_2$ to uniaxial pressure, as well as mapping out parts of its unusual phase diagram.
*Supported by NSF through DMR-0454869 and by Dept. Energy Basic Energy Sciences, contract number DE-AC02-07CH11358.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.MAR.J39.4
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