Magnetoelectric Films Research Articles

Preparation and Exchange Bias of a Cr<sub>2</sub>O<sub>3</sub>/(La<sub>0.7</sub>Sr<sub>0.3</sub>)MnO<sub>3</sub> Magnetic Hetero Junction

We investigated the magnetic interaction between antiferromagnetic, magnetoelectric Cr2O3 film and ferromagnetic La0.7Sr0.3MnO3 film, which shows colossal magneto-resistance. Magnetic properties and structural analyses revealed that a decrease in the thickness of La0.7Sr0.3MnO3 films gives rise to a change in magnetic anisotropy from perpendicular to in-plane. The exchange interaction between Cr2O3 and La0.7Sr0.3MnO3 also changed depending on the magnetic properties of La0.7Sr0.3MnO3. This suggests that the crystallographical control and the selection of a suitable thickness of La0.7Sr0.3MnO3 are important to obtain an exchange interaction in the magnetic hetero system using colossal magneto-resistance material.

Magnetoelectric CoFe2O4-lead zirconate titanate thick films prepared by a polyvinylpyrrolidone-assisted sol-gel method

Magnetoelectric CoFe2O4-PZT (lead zirconate titanate) films as thick as 1μm have been prepared by spin coating using a PZT sol-gel solution containing polyvinylpyrrolidone and CoFe2O4 powder. X-ray diffraction result reveals that there exists no chemical reaction or phase diffusion between the CoFe2O4 and PZT phases. The scanning electron microscopy observation confirms that the composite thick film is crack-free and has a well-defined microstructure. The composite thick films exhibit good magnetic and ferroelectric properties, as well as distinct magnetoelectric coupling behavior. The magnetoelectric coupling mechanism for the present composite thick film is discussed in detail.

Magnetoelectric Phenomena in Nonlinear Optics

Theoretical aspects and experimental observations of nonlinear magnetoelectric phenomena concerning the optical second harmonic generation are discussed. The coexistence of ferroelectric and antiferromagnetic orders in the hexagonal manganites R MnO 3 leads to a new contribution to the nonlinear polarisation. Polarisation selection rules of this contribution allow to determine the magnetic space groups of the hexagonal manganites. Spectroscopic study of second harmonic generation in magnetoelectric garnet films reveals the role of bismuth substitution in these compounds. A new magnetic-dipole mechanism based on magnetoelectric excitation of second harmonic generation in the centrosymmetric antiferromagnet NiO is experimentally studied. Multiphoton resonance gives rise to a high efficiency of this mechanism in NiO.

Lattice effects in the waveguide propagation of a magnetic EH polariton along a macroscopically thin magnetoelectric film

It is shown that the lattice effect is able to induce previously unknown anomalies in the spectrum of the bulk magnetic EH polariton travelling along a macroscopically thin magnetoelectric film even in the presence of total coherent matching of this film to a nonmagnetic coating. The character of these anomalies substantially depends on the relationship between the Neel and Debye temperatures of a magnetic crystal.