• Lue, Chin Shan
• Sonachalam, Arumugam
• Joseph, Boby
• Kuo, Chia Nung

Abstract

<jats:title>Abstract</jats:title><jats:p>Sc<jats:sub>5</jats:sub>Rh<jats:sub>6</jats:sub>Sn<jats:sub>18</jats:sub> with a cage-type quasiskutterudite crystal lattice and type II superconductivity, with superconducting transition temperature <jats:italic>T</jats:italic><jats:sub>c</jats:sub> = 4.99 K, was investigated under hydrostatic high-pressure (HP) using electrical transport, synchrotron x-ray diffraction (XRD) and Raman spectroscopy. Our data show that HP enhance the metallic nature and <jats:italic>T</jats:italic><jats:sub>c</jats:sub> of the system. <jats:italic>T</jats:italic><jats:sub>c</jats:sub> is found to show a continuous increase reaching to 5.24 K at 2.5 GPa. Although the system is metallic in nature, Raman spectroscopy investigations at ambient pressure revealed the presence of three weak modes at 165.97, 219.86 and 230.35 cm<jats:sup>−1</jats:sup>, mostly related to the rattling atom Sc. The HP-XRD data revealed that the cage structure was stable without any structural phase transition up to ∼7 GPa. The lattice parameters and volume exhibited a smooth decrease without any anomalies as a function of pressure in this pressure range. In particular, a second order Birch–Murnaghan equation of state can describe the pressure dependence of the unit cell volume well, yielding a bulk modulus of ∼97 GPa. HP Raman investigations revealed a linear shift of all the three Raman modes to higher wavenumbers with increasing pressure up to ∼8 GPa. As the pressure enhances the bond overlap, thus inducing more electronic charges into the system, HP-XRD and Raman results may indicate the possibility of obtaining higher <jats:italic>T</jats:italic><jats:sub>c</jats:sub> with increasing pressures in this pressure range.</jats:p>

Topics

• impedance spectroscopy
• single crystal
• phase
• x-ray diffraction
• phase transition
• Raman spectroscopy
• bulk modulus
• crystalline lattice
• superconductivity
• superconductivity