Real exchange rate volatility, financial crises and nominal exchange regimes

This paper examines the sources of real exchange rate (RER) volatility in eighty countries around the world, during the period 1970 to 2011. Our main goal is to explore the role of nominal exchange rate regimes and financial crises in explaining the RER volatility. To that end, we employ two complementary procedures that consist in detecting structural breaks in the RER series and decomposing volatility into its permanent and transitory components. The results confirm that exchange rate volatility does increase with the global financial crises and detect the existence of an inverse relationship between the degree of flexibility in the exchange rate regime and RER volatility using a de facto exchange rate classification.

High On/Off ratio memristive switching of manganite/cuprate bilayer by interfacial magnetoelectricity

Memristive switching serves as the basis for a new generation of electronic devices. Memristors are two-terminal devices in which the current is turned on and off by redistributing point defects, e.g., vacancies, which is difficult to control. Memristors based on alternative mechanisms have been explored, but achieving both the high On/Off ratio and the low switching energy desirable for use in electronics remains a challenge. Here we report memristive switching in a La_(0.7)Ca_(0.3)MnO_(3)/PrBa_(2)Cu_(3)O_(7) bilayer with an On/Off ratio greater than 103 and demonstrate that the phenomenon originates from a new type of interfacial magnetoelectricity. Using results from firstprinciples calculations, we show that an external electric-field induces subtle displacements of the interfacial Mn ions, which switches on/off an interfacial magnetic “dead” layer, resulting in memristive behavior for spin-polarized electron transport across the bilayer. The interfacial nature of the switching entails low energy cost about of a tenth of atto Joule for write/erase a “bit”. Our results indicate new opportunities for manganite/cuprate systems and other transition-metal-oxide junctions in memristive applications.