Signature of Magnetic Phase Separation in the Ground State of Pr1-xCaxMnO3

TL;DR

This study uses neutron scattering to reveal magnetic phase separation in Pr1-xCaxMnO3, showing how doping and temperature influence charge and magnetic order, identifying a critical doping level that separates different ground states.

Contribution

It provides direct experimental evidence of magnetic phase separation and identifies a critical doping level in Pr1-xCaxMnO3 that distinguishes phase-separated from homogeneous charge-ordered ground states.

Findings

Spin clusters depend on doping and temperature.

Coexistence of spin clusters with long-range order at x=0.3.

Critical doping x_c around 0.35 separates different ground states.

Abstract

Neutron scattering has been used to investigate the evolution of the long- and short-range charge-ordered (CO), ferromagnetic (FM), and antiferromagnetic (AF) correlations in single crystals of Pr1-xCaxMnO3. The existence and population of spin clusters as refected by short-range correlations are found to drastically depend on the doping (x) and temperature (T). Concentrated spin clusters coexist with long-range canted AF order in a wide temperature range in x = 0.3 while clusters do not appear in x = 0.4 crystal. In contrast, both CO and AF order parameters in the x = 0.35 crystal show a precipitous decrease below ~ 35 K where spin clusters form. These results provide direct evidence of magnetic phase separation and indicate that there is a critical doping x_c (close to x = 0.35) that divides the phase-separated site-centered from the homogeneous bond-centered or charge-disproportionated CO ground state.