arXiv subjects

C V Tomy

Publications and source records attributed to C V Tomy.

3 recordsLinked to original sources

arXiv2014

Effect of nominal substitution of transition metals for excess Fe in Fe_{1+x}Se superconductor

Taking cue from the increase in the superconducting transition temperature (Tc) of Fe1+xSe via nominal (2 wt%) substitution of Cr instead of excess Fe, we have now extended our study with nominal substitution (<=5 wt%) with other transition metals (Ni, Co, Fe, Mn, Cr, V and Ti) in place of excess iron. The Tc is found to increase (maximum ~11 K) or get suppressed depending on the substituted transition metal. Our studies indicate that the superconducting transition temperature depends on various parameters like the ionic size of the transition metal, its magnetic moment as well as the amount of hexagonal phase present as impurity.

cond-mat.supr-con↗

arXiv2010

Enhanced superconducting properties in FeCr$_x$Se

We report an enhancement of superconducting transition temperature ($T_{\rm c}$) when Chromium (Cr) is substituted in excess at the Iron (Fe) site (FeCr$_x$Se, $x=$0.01, 0.02 and 0.03). There is a corresponding increase in the superconducting volume fraction with $T_{\rm c}$ attaining a value of 11.2 K on 2 $%$ Cr substitution when compared to a $T_{\rm c}$ of 8.5 K for the conventional tetragonal Fe-excess sample Fe$_{1+x}$Se. The results point to the role of chemical pressure (introduced via ionic size variation at the Fe site upon Cr substitution in excess) on superconducting properties.

cond-mat.supr-con↗

arXiv2005

Pulverization of the flux line lattice, the phase coexistence and the spinodal temperature of the order-disorder transition in a weakly pinned crystal of Yb$_3$Rh$_4$Sn$_{13}$

We have studied metastability effects pertaining to the peak effect (PE) in critical current density ($J_c$) via isofield scans in ac susceptibility measurements in a weakly pinned single crystal of Yb$_3$Rh$_4$Sn$_{13}$ ($T_c(0) \approx 7.6 $~K). The order-disorder transition in this specimen proceeds in a multi-step manner. The phase coexistence regime between the onset temperature of the PE and the spinodal temperature (where metastability effects cease) seems to comprise two parts, where ordered and disordered regions dominate the bulk behavior, respectively. The PE line in the vortex phase diagram is argued to terminate at the low field end at a critical point in the elastic (Bragg) glass phase.

cond-mat.supr-con↗