Phase formation, phonon behavior, and magnetic properties of novel ferromagnetic La3BAlMnO9 (B = Co or Ni) triple perovskites

TL;DR

This study investigates the synthesis, structural properties, and magnetic behavior of novel La3BAlMnO9 (B = Co or Ni) triple perovskite thin films, revealing their ferromagnetic transition temperatures and the effects of AlO6 octahedra on magnetic interactions.

Contribution

It introduces new La3BAlMnO9 triple perovskites, explores their growth conditions, and analyzes how AlO6 octahedra influence magnetic and multiferroic properties.

Findings

La3CoAlMnO9 is ferromagnetic up to 190 K.

La3NiAlMnO9 has a Curie temperature of 130 K.

Insertion of AlO6 octahedra reduces superexchange strength.

Abstract

In the quest for novel magnetoelectric materials, we have grown, stabilized and explored the properties of La3BAlMnO9 (B = Co or Mn) thin films. In this paper, we report the influence of the growth parameters that promote B/Al/Mn ordering in the pseudo-cubic unit cell and their likely influence on the magnetic and multiferroic properties. The temperature dependence of the magnetization shows that La3CoAlMnO9 is ferromagnetic up to 190 K while La3NiAlMnO9 shows a TC of 130 K. The behavior of these films are compared and contrasted with related La2BMnO6 double perovskites. It is observed that the insertion of AlO6 octahedra between CoO6 and MnO6 suppresses significantly the strength of the superexchange interaction, spin-phonon and spin-polar coupling.