Magnetic evolution of itinerant ferromagnetism and interlayer antiferromagnetism in cerium doped LaCo2P2 crystals

ThCr2Si2-type phosphide ACo2P2 (A=Eu, La, Pr, Nd, Ce) has the same structure as iron arsenides, but their magnetic behaviors are quite distinct. In this paper, we grew a series of La1−xCexCo2P2 single crystals (x=0.0 to1.0), made structural and magnetic characterizations. We found the introduction of cerium induces a rapid decrease of c-axis and a change from ferromagnetic to antiferromagnetic states. Compared to other trivalent doped compounds, the enhancement of ferromagnetism with doping is suppressed and the transition from ferromagnetism to antiferromagnetism appear earlier. By employing first-principles band-structure calculations, we identify the increase of Ce valence suppress the itinerant ferromagnetism and leading to formation of P-P bonding with the shortening of c-axis. The bonding effectively drives an increase of interlayer antiferromagnetic interaction, eventually leads to antiferromagnetic ordering of cobalt in high-doping region.