Growth of EuO single crystals at reduced temperatures

TL;DR

This study reports the growth of EuO single crystals doped with barium at reduced temperatures and explores how Ba doping influences magnetic properties, suggesting a possible quantum phase transition at high doping levels.

Contribution

It introduces a method to grow EuO crystals with controlled Ba doping at lower temperatures and models the doping dependence of their magnetic transition temperatures.

Findings

Ba doping increases the Curie temperature up to a certain level

A modified Heisenberg model describes the doping dependence of T_C

Extrapolation suggests a quantum phase transition at x=0.72

Abstract

Single crystals of (Eu$_{1-x}$Ba$_x$)O have been grown in a molten barium-magnesium metal flux at temperatures up to 1000{\deg}C, producing single crystals of (Eu$_{1-x}$Ba$_x$)O with barium doping levels ranging from $x=0.03$ to $x=0.25$. Magnetic measurements show that the ferromagnetic Curie temperature T$_C$ correlates with the Ba doping levels, and a modified Heisenberg model was used to describe the stoichiometry dependence of T$_C$. Extrapolation of the results indicates that a sample with Ba concentration of $x=0.72$ should have a T$_C$ of 0 K, potentially producing a quantum phase transition in this material.