Phase diagram of CeFeAs$_{1-x}$P$_{x}$O obtained from electric resistivity, magnetization, and specific heat measurements

TL;DR

This study maps the phase diagram of CeFeAs$_{1-x}$P$_{x}$O using resistivity, magnetization, and heat capacity, revealing magnetic transitions, heavy-fermion behavior, and the absence of superconductivity across doping levels.

Contribution

It provides a comprehensive experimental phase diagram of CeFeAs$_{1-x}$P$_{x}$O, highlighting magnetic quantum phase transitions and the evolution of electronic states with P doping.

Findings

Magnetic quantum phase transition occurs around x ≈ 0.4.

Ferromagnetic order develops near x ≈ 0.4 and vanishes near x=0.9.

Heavy-fermion-like behavior appears for x ≥ 0.95.

Abstract

We performed a systematic study on the properties of CeFeAs$_{1-x}$P$_{x}$O ($0\leq x\leq 1$) by electrical resistivity, magnetization and specific heat measurements. The c-axis lattice constant decreases significantly with increasing P content, suggesting a remarkable chemical pressure. The Fe-3d electrons show the enhanced metallic behavior upon P-doping and undergo a magnetic quantum phase transition around $x \approx 0.4$. Meanwhile, the Ce-4f electrons develop a ferromagnetic order near the same doping level. The ferromagnetic order is vanishingly small around $x=0.9$. The data suggest a heavy-fermion-like behavior as $x\geq 0.95$. No superconductivity is observed down to 2 K. Our results show the ferromagnetic ordered state as an intermediate phase intruding between the antiferromagnetic bad metal and the nonmagnetic heavy fermion metal and support the cerium-containing iron pnictides as a unique layered Kondo lattice system.