FORMATION MECHANISM OF SPOTANEOUS SUPERLATTICE BY APPLICATION OFMAGNETIC FIELD DURING DEPOSITION AND STRUCTURE INDUCED FERROELECTRICITY

在Nb-SrTiO_3(001)单晶衬底上用PLD方法在磁场中沉积了具有过量组分的同质外延生长的SrTiO_3薄膜，观察到了超晶格的自发形成。结果表明，这一现象是由表面定向调幅分解引起的。该薄膜即使在室温下也表现出铁电性。这种现象是由在不同成分的层的界面上形成的内部应变引起的。

Spontaneous formation of superlattice is observed for homoepitaxially grown SrTiO3thin film with Sr-excess composition deposited on Nb-SrTiO3(001) single crystal substrate when the film was deposited using PLD in the magnetic field. It was clarified that this phenomenon is caused by surface-directed spinodal decomposition. This film shows ferroelectricity even at room temperature. This phenomenon would be caused by the internal strain that forms at the interface of layers with different composition.