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A new class of half-metallic ferromagnets has been found in the zinc-blende crystal structure. The previously nonexistent zinc-blende CrAs thin films have been synthesized on GaAs (001) substrates by molecular-beam epitaxy, and show a ferromagnetic behavior at room temperature. The zinc-blende CrAs has been designed by ab initio calculations based on the local spin-density approximation, and the calculation predicts the highly spin-polarized electronic band structure.

Exotic features of a metal/oxide/metal (MOM) sandwich, which will be the basis for a drastically innovative nonvolatile memory device, is brought to light from a physical point of view. Here the insulator is one of the ubiquitous and classic binary-transition-metal oxides (TMO), such as Fe2O3, NiO, and CoO. The sandwich exhibits a resistance that reversibly switches between two states: one is a highly resistive off-state and the other is a conductive on-state. Several distinct features were universally observed in these binary TMO sandwiches: namely, nonpolar switching, non-volatile threshold switching, and current-voltage duality. From the systematic sample-size dependence of the resistance in on-and off-states, we conclude that the resistance switching is due to the homogeneous/inhomogeneous transition of the current distribution at the interface.

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The resistance switching properties in Pt∕Ni–O∕Pt and Pt∕Co–O∕Pt synthesized by the magnetron sputtering have been investigated. The oxygen partial pressure during sputtering and the post-thermal process are crucial to forming of the trilayer. By investigating x-ray photoemission spectroscopy spectra, the increase of initial resistance in Ni–O was caused by the variation of the stoichiometry, while that in the Co–O was accompanied by the phase transformation between CoO and Co3O4. The resistance switching in Pt∕Co–O∕Pt and Pt∕Ni–O∕Pt exhibits the analogous electrode area and temperature dependences. As a result of the I-V measurements at the elevated temperature, the assistance of Joule heating in the reset process is implied.