More ferroelectrics discovered by switching spectroscopy piezoresponse force microscopy?

The local hysteresis loop obtained by switching spectroscopy piezoresponse force microscopy (SS-PFM) is usually regarded as a typical signature of ferroelectric switching. However, such hysteresis loops were also observed in a broad variety of non-ferroelectric materials in the past several years, which casts doubts on the viewpoint that the local hysteresis loops in SS-PFM originate from ferroelectricity. Therefore, it is crucial to explore the mechanism of local hysteresis loops obtained in SS-PFM testing. Here we proposed that non-ferroelectric materials can also exhibit amplitude butterfly loops and phase hysteresis loops in SS-PFM testing due to the Maxwell force as long as the material can show macroscopic D-E hysteresis loops under cyclic electric field loading, no matter what the inherent physical mechanism is. To verify our viewpoint, both the macroscopic D-E and microscopic SS-PFM testing are conducted on a soda-lime glass and a non-ferroelectric dielectric material Ba0.4Sr0.6TiO3. Results show that both materials can exhibit D-E hysteresis loops and SS-PFM phase hysteresis loops, which can well support our viewpoint.Comment: 12 pages,4 figure

Fingerprinting Hysteresis

We test the predictive power of first-oder reversal curve (FORC) diagrams using simulations of random magnets. In particular, we compute a histogram of the switching fields of the underlying microscopic switching units along the major hysteresis loop, and compare to the corresponding FORC diagram. We find qualitative agreement between the switching-field histogram and the FORC diagram, yet differences are noticeable. We discuss possible sources for these differences and present results for frustrated systems where the discrepancies are more pronounced.Comment: 4 pages, 5 figure

Hysteresis and unemployment : a preliminary investigation

This paper points out what hysteresis is using a simple model of market entry and exit. A procedure for calculating hysteresis indices for economic time series is outlined. Some preliminary results are presented to assess the explanatory power of hysteresis variables with regard to the equilibrium rate of unemployment in the UK. We find that both natural and "unnatural" variables enter a cointegrating vector for UK unemployment 1959-1996. The natural variable is the replacement ratio. The 'unnatural' variables are the hysteresis index of the exchange rate; and hysteresis indices for the real oil price and the real interest rate

Hysteresis

Three competing conceptualizations of hysteresis in economics are identified: the unit/zero root approach, “true” hysteresis, and hysteresis conceived as a product of historical time. The properties of these conceptualizations are discussed and their pros and cons considered.hysteresis, path dependence, unit root, historical time

Effects of cycling on lithium-ion battery hysteresis and overvoltage

Currently, lithium-ion batteries are widely used as energy storage systems for mobile applications. However, a better understanding of their nature is still required to improve battery management systems (BMS). Overvoltages and open-circuit voltage (OCV) hysteresis provide valuable information regarding battery performance, but estimations of these parameters are generally inaccurate, leading to errors in BMS. Studies on hysteresis are commonly avoided because the hysteresis depends on the state of charge and degradation level and requires time-consuming measurements. We have investigated hysteresis and overvoltages in Li(NiMnCo)O2/graphite and LiFePO4/graphite commercial cells. Here we report a direct relationship between an increase in OCV hysteresis and an increase in charge overvoltage when the cells are degraded by cycling. We fnd that the hysteresis is related to difusion and increases with the formation of pure phases, being primarily related to the graphite electrode. These fndings indicate that the graphite electrode is a determining factor for cell efciency.Peer ReviewedPostprint (published version