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Ferroelectric K0.5Na0.5NbO3 (KNN) thin film was epitaxially grown on La0.67Sr0.33MnO3 (LSMO) buffered LaAlO3 substrate by pulse laser deposition. The crystallographic structure of KNN/LSMO was confirmed by x-ray diffraction. Interestingly, a dielectric relaxor feature was found in the temperature range 200–350 °C. The activation energies for relaxation and conduction of the films were found to be 1.87 and 0.63–0.71 eV, respectively. The mechanism for dielectric relaxation in KNN/LSMO structure was discussed under a thermally activated process. The remnant polarization and coercive field of the films were 21.3 μC/cm2 and 91 kV/cm, respectively. [ABSTRACT FROM AUTHOR]

The exchange bias effect has been observed in the superlattices consisting of ferromagnetic La0.67Sr0.33MnO3 and nonmagnetic insulating SrTiO3 layers. It is found that the exchange field shows an oscillatory decay with a period of ∼12 unit cells and approaches to a constant value of -100 Oe when the SrTiO3 thickness is increased. The tunneling current also displays a nonmonotonic decrease with the SrTiO3 thickness. These observations can be discussed on the basis of the interlayer exchange coupling between La0.67Sr0.33MnO3 layers via the spin-polarized electrons tunneling across the SrTiO3 spacers. [ABSTRACT FROM AUTHOR]

Epitaxial Ba0.15Zr0.85TiO3 (BZT) ferroelectric thin films with (001), (011), and (111) orientations were, respectively, grown on La0.67Sr0.33MnO3 (LSMO) buffered LaAlO3 substrates by pulsed laser deposition method. The dc electric-field dependence of permittivity and dielectric loss of (001)-, (011)-, and (111)-oriented BZT/LSMO heterostructures obeys the Johnson formula, and the ac electric-field dependence of that obeys the Rayleigh law under the subswitching field region. The anisotropic dielectric properties are attributed to the higher mobility of the charge carriers, the concentration of mobile interfacial domain walls, and boundaries in the (111)-oriental films than in the (110)- and (100)-oriented films. [ABSTRACT FROM AUTHOR]

We use magnetism and specific heat measurements to investigate the hexagonal Mn-rich YMnO3. It is found that upon cooling from a high temperature, the compound first orders antiferromagnetically at TN∼72 K and then undergoes a re-entrant spin glass (RSG) transition at TSG∼42 K. This RSG behavior results from the competition between the ferromagnetic interaction and the antiferromagnetic interaction, which is related to the intrinsic geometric magnetic frustration in this system. [ABSTRACT FROM AUTHOR]

We use magnetism and specific heat measurements to investigate the hexagonal Mn-rich YMnO3. It is found that upon cooling from a high temperature, the compound first orders antiferromagnetically at TN∼72 K and then undergoes a re-entrant spin glass (RSG) transition at TSG∼42 K. This RSG behavior results from the competition between the ferromagnetic interaction and the antiferromagnetic interaction, which is related to the intrinsic geometric magnetic frustration in this system. [ABSTRACT FROM AUTHOR]