Striped Multiferroic Phase in Double-Exchange Model for Quarter-Doped Manganites

TL;DR

This paper investigates the phase diagram of quarter-hole-doped manganites using the double-exchange model, revealing a new striped multiferroic phase with enhanced Curie temperature and similar polarization to spiral-spin phases.

Contribution

It introduces a novel striped multiferroic phase in the double-exchange model, highlighting a new mechanism for noncollinear spin multiferroics based on electronic self-organization.

Findings

Discovery of a striped type-II multiferroic phase in manganites.

The multiferroic Curie temperature is approximately four times higher than in undoped phases.

The ferroelectric polarization magnitude is comparable to spiral-spin phases.

Abstract

The phase diagram of quarter-hole-doped perovskite manganites is investigated using the doubleexchange model. An exotic striped type-II multiferroic phase, where 25% of the nearest-neighbor spin couplings are orthogonal to each other, is found in the narrow-bandwidth region. Comparing with the spiral-spin ordering phase of undoped manganites, the multiferroic Curie temperature of the new phase is estimated to be ~4 times higher, while the ferroelectric polarization is similar in magnitude. Our study provides a path for noncollinear spin multiferroics based on electronic self-organization, different from the traditional approach based on superexchange frustration.