Magnetization plateaus in Ca3Co2O6 thin films

Abstract

Continuous Ca₃Co₂O₆ thin films were fabricated on Al₂O₃(001) substrate by pulsed laser deposition. X-ray diffraction and cross-section transmission electron microscopy show that the deposited films are polycrystalline without any secondary phases. The magnetic properties of the films are similar to those reported for bulk polycrystalline samples. At low temperatures, the films exhibit a magnetic transition at 20 K towards a 3D long range ferrimagnetic order. At 10 and 2 K, steps of magnetization have been observed and related to the ferrimagnetic–ferromagnetic transition and to magnetization quantum tunneling phenomena, respectively. This behavior is promoted by the frustrated antiferromagnetic interaction between the Ising-type Co chains of Ca₃Co₂O₆ and by the spin configuration of the octahedral Co³⁺ ions. Such layers with magnetic properties similar to those of the bulk were obtained here for the first time. This result opens new perspective for the integration of these materials in thermoelectric or spintronic devices.