In 2008, researchers at the Hewlett-Packard (HP) laboratories published a paper in Nature reporting the development of a new basic circuit element that completes the missing link between charge and flux linkage, which was postulated by Chua in 1971(Chua 1971 IEEE Trans. Circuit Theory 18, 507-519 (doi:10.1109/TCT.1971). The HP memristor is based on a nanometre scale TiO 2 thin film, containing a doped region and an undoped region. Further to proposed applications of memristors in artificial biological systems and non-volatile RAM, they also enable reconfigurable nanoelectronics. Moreover, memristors provide new paradigms in application-specific integrated circuits and field programmable gate arrays. A significant reduction in area with an unprecedented memory capacity and device density are the potential advantages of memristors for integrated circuits. This work reviews the memristor and provides mathematical and SPICE models for memristors. Insight into the memristor device is given via recalling the quasi-static expansion of Maxwell's equations. We also review Chua's arguments based on electromagnetic theory.

The magnetization behaviours have been analyzed for as‐quenched and annealed Fe91–xYxZr9 (x = 0, 5, 10) alloys. Samples were prepared by arc melting the high‐purity elemental constituents under argon gas atmosphere and by single roller melt spinning. These alloys were annealed one hour at 500 °C. The magnetic properties of the samples were measured by VSM. The Curie temperature increases with increasing Y concentration (x = 0 to 10). Temperature dependence of the entropy variation ΔSM was found to appear in the vicinity of the Curie temperature. The results show that annealed Fe86Y5Zr9 alloys have a greater magnetocaloric effect than that those in as‐quenched alloys. The value is ‐1.23 J/kg K at ΔH = 1.5 T for annealed alloy and ‐0.89 for as‐quenched alloy, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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