Ferromagnetic insulating phase in Pr{1-x}Ca{x}MnO3

TL;DR

This study investigates the ferromagnetic insulating phase in Pr0.75Ca0.25MnO3 through neutron scattering and theoretical modeling, revealing a unique state characterized by weak Jahn-Teller distortion and isotropic magnetic interactions, distinct from typical phase separation or charge ordering.

Contribution

It presents the first detailed neutron scattering and theoretical analysis of the ferromagnetic insulating phase in Pr0.75Ca0.25MnO3, highlighting its unique lattice and magnetic properties.

Findings

Insulating behavior is robust against magnetic fields.

Weak Jahn-Teller distortion compared to PrMnO3.

Theoretical model reproduces spin and orbital features.

Abstract

A ferromagnetic insulating (FM-I) state in Pr0.75Ca0.25MnO3 has been studied by neutron scattering experiment and theoretical calculation. The insulating behavior is robust against an external magnetic field, and is ascribed to neither the phase separation between a ferromagnetic metallic (FM-M) phase and a non-ferromagnetic insulating one, nor the charge ordering. We found that the Jahn-Teller type lattice distortion is much weaker than PrMnO3 and the magnetic interaction is almost isotropic. These features resembles the ferromagnetic metallic state of manganites, but the spin exchange interaction J is much reduced compared to the FM-M state. The theoretical calculation based on the staggered type orbital order well reproduces several features of the spin and orbital state in the FM-I phase.