Evolution of magnetism in cerium doped LaCo2P2 crystals: a magnetic phase diagram

TL;DR

This study investigates how cerium doping affects the magnetic properties of LaCo2P2 crystals, revealing a transition from ferromagnetic to antiferromagnetic states and constructing a detailed magnetic phase diagram.

Contribution

First comprehensive growth and characterization of La1-xCexCo2P2 crystals, linking cerium content to magnetic phase evolution and structural changes.

Findings

Cerium doping causes a rapid decrease in c-axis length.

Transition from ferromagnetic to antiferromagnetic states with increased cerium.

P-P bonding formation correlates with magnetic and structural changes.

Abstract

ThCr2Si2-type phosphide ACo2P2 (A=Rare earth elements) has the same structure as iron arsenides, but their magnetic behaviors are quite distinct. In this paper, we for the first time grew a series of La1-xCexCo2P2 single crystals (x=0.0 to1.0), and made structural and magnetic characterizations. This allows us to carry out a careful investigation on the evolution of magnetism with cerium content and build a magnetic phase diagram. We found that the introduction of cerium induces a rapid decrease of c-axis and a change from ferromagnetic (FM) to antiferromagnetic (AFM) states. By employing first-principles band-structure calculations, we identify the formation of P-P bonding with the shortening of c-axis, which effectively drives an increase of AFM interaction and eventually leads to AFM ordering in the high doping region. The present study may shed light on the interplay between the structural collapsing and electronic/magnetic properties in 122 iron pnictides.