Spin and phonon anomalies in epitaxial self-assembled CoFe2O4-BaTiO3 multiferroic nanostructures

Abstract

Temperature dependent magnetic and phonon anomalies in epitaxial self-assembled CoFe2O4 (CFO) rods embedded in BaTiO3 (BTO) matrix nanostructures were investigated. The temperature dependence of A1(2TO) phonon frequency of BTO indicates that the BTO matrix experiences structural transformations. The lattice strain produced during the structural transformations drives spin reorientation in CFO rods, resulting in anomalous changes of magnetization. Through correlating the phonon anomalies with the increase of in-plane spin ordering, we show the spin-phonon coupling induces the softening of A1g and A1(2TO) phonons. It suggests that spin strongly couples with lattice strain and phonons in this nanostructure.