Evolution of ferromagnetic order in URhGe alloyed with Ru, Co and Si

TL;DR

This study explores how chemical substitution with Ru, Co, and Si affects the ferromagnetic order in URhGe, revealing suppression or enhancement of Curie temperature and identifying potential candidates for ferromagnetic instability research.

Contribution

It provides detailed experimental insights into how Ru, Co, and Si doping modulates ferromagnetic order in URhGe, highlighting the suppression and enhancement of Curie temperatures.

Findings

Ru doping suppresses $T_C$ to zero at $x \\approx 0.38$.

Co doping causes a broad maximum in $T_C$ near $x=0.6$.

Si doping leaves $T_C$ roughly constant.

Abstract

We have investigated the evolution of ferromagnetic order in the correlated metal URhGe (Curie temperature $T_{\rm C} = $9.5 K) by chemical substitution of Ru, Co and Si. Polycrystalline samples URh$_{1-x}$Ru$_x$Ge ($x \leq $0.6), URh$_{1-x}$Co$_x$Ge ($x \leq $0.9) and URhGe$_{1-x}$Si$_x$ ($x \leq $0.2) have been prepared and the magnetic properties have been investigated by magnetization and transport experiments. In the case of Ru doping, $T_{\rm C}$ initially increases, but then decreases linearly as a function of $x$ and is completely suppressed for $x_{\rm cr} \approx 0.38$. The Curie temperature in the URh$_{1-x}$Co$_x$Ge series has a broad maximum $T_{\rm C} = 20$ K near $x=0.6$ and then drops to 8 K for $x=0.9$. In the case of Si doping $T_{\rm C}$ stays roughly constant. We conclude that the alloy systems URh$_{1-x}$Ru$_x$Ge and URh$_{1-x}$Co$_x$Ge are interesting candidates to study the ferromagnetic instability.