A new type of graphene-based quantum Hall standards is tested for electrical quantum metrology applications at alternating current (ac) and direct current (dc). The devices are functionalized with Cr(CO)3 to control the charge carrier density and have branched Hall contacts based on NbTiN superconducting material. The work is an in-depth study about the characteristic capacitances and related losses in the ac regime of the devices and about their performance during precision resistance measurements at dc and ac.

The mutual control of the electric and magnetic properties of a multiferroic solid is of fundamental and great technological importance. In this article, the synthesis procedure of La0.2Pb0.7Fe12O19 ceramics was briefly described and the data acquired for the materials characterization is presented. This data article is related to the research article-Acta Mater. 2016, 121, 144 (j.actamat.2016.08.083). Electric polarization hysteresis loop and I-V curve, which help to confirm the ferroelectricity of La0.2Pb0.7Fe12O19 ceramics, were presented. Strong magnetic polarization data was also presented. The great variation of the dielectric constants along with the magnetic field has been presented which helped to demonstrat the giant magnetocapacitance of La0.2Pb0.7Fe12O19. All the datasets were collected at room temperature. Large ferroelectricity, strong magnetism and colossal magneto-capacitance effect have been all realized in one single phase La0.2Pb0.7Fe12O19 at room temperature.

The coupling between magnetization and polarization in a room temperature multiferroic (Pb(Zr,Ti)O3 -Pb(Fe,Ta)O3 ) is explored by monitoring the changes in capacitance that occur when a magnetic field is applied in each of three orthogonal directions. Magnetocapacitance effects, consistent with P(2) M(2) coupling, are strongest when fields are applied in the plane of the single crystal sheet investigated.

Bilayer thin films of BiFeO3-BaTiO3 at different thicknesses of BiFeO3 were prepared by RF-magnetron sputtering technique. A pure phase polycrystalline growth of thin films was confirmed from XRD results. Significantly improved ferroelectric polarization (2Pr ∼ 30 μC/cm(2)) and magnetic moment (Ms ∼ 33 emu/cc) were observed at room temperature. Effect of ferroelectric polarization on current conduction across the interface has been explored. Accumulation and depletion of charges at the bilayer interface were analyzed by current-voltage measurements which were further confirmed from hysteretic dynamic resistance and capacitance voltage profiles. Magnetoelectric coupling due to induced charges at grain boundaries of bilayer interface was further investigated by room temperature magnetocapacitance analysis. A room temperature magnetocapacitance was found to originate from induced charge at the bilayer interface which can be manipulated by varying the thickness of BFO to obtain higher ME coupling coefficient. Dynamic magnetoelectric coupling was investigated, and maximum longitudinal magnetoelectric coupling was observed to be 61 mV/cm·Oe at 50 nm thickness of BiFeO3. The observed magnetoelectric properties are potentially useful for novel room temperature magnetoelectric and spintronic device applications.