Stabilization and functional properties of La3NiAlMnO9 and La3CoAlMnO9 magnetoelectric triple perovskites

TL;DR

This study reports the stabilization and characterization of La3NiAlMnO9 and La3CoAlMnO9 triple perovskite thin films, highlighting their ferromagnetic properties and strong spin-lattice coupling near phase transitions.

Contribution

It introduces the synthesis and analysis of new La-based triple perovskite thin films with specific magnetic and structural properties, expanding the understanding of magnetoelectric materials.

Findings

LCAMO exhibits ferromagnetism up to 190 K.

LNAMO exhibits ferromagnetism up to 130 K.

Strong spin-lattice-polarization coupling observed in LCAMO.

Abstract

Ferromagnetic La3NiAlMnO9 (LNAMO) and La3CoAlMnO9 (LCAMO) triple-perovskite thin films are stabilized in the 750-860 oC temperature range in 100 to 900 mTorr O2 pressure range using pulsed-laser deposition. The LCAMO and LNAMO films exhibit ferromagnetism up to 190 K and 130 K respectively. The structural, optical and magnetic properties of these films demonstrate that the B-site 3d-cations, Al, Mn and Co or Ni ions, are structurally short-range ordered. The strong spin-lattice-polarization coupling in LCAMO is evidenced by the temperature dependence of the dielectric constant and the softening of the phonon frequencies starting in the vicinity of the ferromagnetic-to-paramagnetic phase transition mimicking the behaviours of La2CoMnO6 double perovskite.