Excellent Energy Storage Performance in Bi(Fe0.93Mn0.05Ti0.02)O3 Modified CaBi4Ti4O15 Thin Film by Adjusting Annealing Temperature

Editorial for the Special Issue "Nanoscale Ferroic Materials-Ferroelectric, Piezoelectric, Magnetic, and Multiferroic Materials"

Ferroic materials, including ferroelectric, piezoelectric, magnetic, and multiferroic materials, are receiving great scientific attentions due to their rich physical properties [...].

Investigation into Layer Number Effect on Breakdown Strength of Multi-Layer Polymer Films

The layer number effect on electric breakdown strength (E_BD) of multi-layer polymer films is investigated using 10-μm polypropylene (PP) films under a dc condition. The layer number, n, of the films during the test is as large as 120. It is observed that the relation between E_BD and n conforms to a minus power law, i.e., E_BD(n) = E_1′n^−a, where the power exponent, a, is 0.27, E_1′ is a constant. By reviewing the experimental data in references, it is found that the power law holds true for different types of polymers in different test conditions, but the value of a varies from 0.072 to 0.5. The variation of a is explained in perspective of the discontinuous structures within films and those between films. A small value of a means a good purity level of the film, which is due to the decrease of the size of the inter-layer defects. A large value of a means a poor purity level of the films, which is due to the increase of the amount of intra-layer defects. Both factors influence the value of a, leading to the variation of a.