Dielectric anomalies in orthorhombic YMnO3 thin films

• Published in: Thin solid films 2010-06, Vol.518 (16), p.4710-4713
• Main Authors: FINA, I, MARTI, X, FABREGA, L, SANCHEZ, F, FONTCUBERTA, J
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric loss; Dielectric strength; Dielectric thin films; Dielectrics; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Joining; Magnetic fields; Magnetic properties; Niobium; Origins; Physics; Thin films
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2009.12.065

We report on the magnetodielectric characterization of orthorhombic (001) oriented YMnO3 thin films grown by PLD on Nb-doped SrTiO3. Detailed temperature, magnetic field and frequency dependent measurements are used to determine dielectric and magnetodielectric response and to analyse its origin. A dielectric peak below the Neel temperature is observed. We show that this peak signals a magnetoelectric coupling as inferred from a magnetocapacitance of about 2% at 8T and 25K. A careful analysis of the impedance spectroscopy allows concluding that both the dielectric peak and the measured magnetocapacitance are intrinsic properties of YMnO3. At higher temperatures (>200K) another dielectric feature (a strong frequency dependency and a peak in the dielectric losses) is observed, which is ascribed to the Maxwell-Wagner behaviour and thus it is not a genuine response of stoichiometric YMnO3.