Dielectric, Impedance, Magnetic and Magnetoelectric Measurements on YMnO₃

A microwave power absorption characterization of YMnO3

“…The temperature dependence of the dielectric constant, as well as impedance measurements at several selected rf frequency values, are reported in Ref. [9] on polycrystalline YMnO 3 ; this measurements show relaxations close to the transition temperature T i . The thermal variations of MPA are therefore indicative of a dielectric process, A, and the set-in of another dynamics of absorption, C, are mainly due to relaxations of the electric dipoles.The previous behaviors contrast with those observed in magnetically ordered materials as it appears in Fig.…”

“…This coupling can result in the so-called magnetoelectric effect, where the magnetic (dielectric) properties of the material may be altered by the onset of the electric (magnetic) transition or by the application of an electric (magnetic) field. To investigate this coupling, the material is typically excited with a magnetic (electric) field and the observation of a typical electric (magnetic) response such as dielectric permittivity (magnetic susceptibility) is carried out [3,9]. Additionally, anomalies in the dielectric constant and loss tangent have been observed near the Néel temperature [5], when the material is driven through a phase transition.…”

“…The material under study has shown to have a coupling between the electric and magnetic phenomena [3,9]; the MPA is therefore expected to be due to both magnetic and electric dipoles contained in the material.…”

Perovskite Electrocatalysts for the Oxygen Reduction Reaction in Alkaline Media

“…No discernable trend could be identified for substitution of the A-site from La to Dy [74][75][76][77][78][79][80] (Figure 2g) under the caveat that some of the data was only available for temperatures >300 K (Table A2). For the ORR data of Suntivich et al [22], the activity trend matches that of the typical conductivity of the used LaBO 3 perovskites.…”

Nano-Structured Oxides for the Next Generation of Electrooptic Devices

“…More precisely, if you do so, the numerical values of R, L, and C change rather rapidly and unprediuctably with temperature and especially frequency. However, the frequency dependence can be greatly [28] simplified if a constant phase element (CPE) is included [23]. The origin of such CPEs is in general unknown from microscopic physics, but always involves an inhomogeneity in the system; for ferroelectrics this is usually the domain walls [24,25].…”