Carrier-doping effect and anomalous transport properties in Ni-doped CeCoIn5 investigated by Hall resistivity measurements

TL;DR

This study examines how Ni doping influences carrier density and anomalous transport in CeCoIn5, revealing that Ni acts as an electron dopant and suppresses Hall resistivity anomalies near critical fields.

Contribution

It provides the first detailed analysis of Ni doping effects on carrier density and Hall resistivity anomalies in CeCoIn5 using Hall measurements.

Findings

Carrier density increases linearly with Ni doping level.

Ni doping suppresses Hall resistivity anomalies near critical fields.

Ni acts as an electron dopant in CeCoIn5.

Abstract

We investigated the effects of Ni doping on carrier density and anomalous electrical transport properties in CeCo$_{1-x}$Ni$_x$In$_5$ ($x \leq 0.3$) by performing Hall resistivity measurements. The carrier density, estimated from the Hall coefficient $R_{\rm H}$ at a temperature of 0.5 K in high magnetic fields, increases linearly with $x$, indicating that the doped Ni ions act as electron dopants. In CeCoIn$_5$, the magnitude of $-R_{\rm H}$ is strongly enhanced at magnetic fields near the superconducting upper critical field $H_{c2}$ and in the low-field region above the superconducting transition temperature $T_c$. However, these anomalies are found to be significantly suppressed by Ni doping. Possible origins of this suppression in $-R_{\rm H}$ are discussed.