Magnetic effects at the interface between nonmagnetic oxides

The electronic reconstruction at the interface between two insulating oxides can give rise to a highly-conductive interface. In analogy to this remarkable interface-induced conductivity we show how, additionally, magnetism can be induced at the interface between the otherwise nonmagnetic insulating perovskites SrTiO3 and LaAlO3. A large negative magnetoresistance of the interface is found, together with a logarithmic temperature dependence of the sheet resistance. At low temperatures, the sheet resistance reveals magnetic hysteresis. Magnetic ordering is a key issue in solid-state science and its underlying mechanisms are still the subject of intense research. In particular, the interplay between localized magnetic moments and the spin of itinerant conduction electrons in a solid gives rise to intriguing many-body effects such as Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions, the Kondo effect, and carrier-induced ferromagnetism in diluted magnetic semiconductors. The conducting oxide interface now provides a versatile system to induce and manipulate magnetic moments in otherwise nonmagnetic materials.Comment: Nature Materials, July issu

Spatial and temporal evolution of PLD plasmas

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Laminated CeO\u3csub\u3e2\u3c/sub\u3e/HfO\u3csub\u3e2\u3c/sub\u3e high-k gate dielectrics grown by pulsed laser deposition in reducing ambient

\u3cp\u3eCeO\u3csub\u3e2\u3c/sub\u3e and HfO\u3csub\u3e2\u3c/sub\u3e dielectric layers were deposited in an Ar+(5%)H\u3csub\u3e2\u3c/sub\u3e gas mixture by Pulsed Laser Deposition (PLD) on Si (100). A CeO\u3csub\u3e2\u3c/sub\u3e-Ce\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e transformation is achieved by deposition in a reducing ambient. It is also shown that in-situ post deposition anneal efficiently oxidizes Ce\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e layers to CeO \u3csub\u3e2\u3c/sub\u3e. The properties of CeO\u3csub\u3e2\u3c/sub\u3e/HfO\u3csub\u3e2\u3c/sub\u3e laminated structures deposited in reducing ambient and compared with binary oxide layers of CeO\u3csub\u3e2\u3c/sub\u3e and HfO\u3csub\u3e2\u3c/sub\u3e. The effect of the layer sequence, individual layer thickness and deposition temperature on the structural and electrical properties of the laminates were investigated. It is found that the layer sequence of the laminates affects the crystallinity of the layers and changes the electrical properties. The amorphous laminate with a CeO\u3csub\u3e2\u3c/sub\u3e starting layer with 4 nm physical thickness and an EOT of 2 nm, has the lowest J@V\u3csub\u3efb\u3c/sub\u3e-1 V=1.88 × 10\u3csup\u3e-7\u3c/sup\u3e A/cm\u3csup\u3e2\u3c/sup\u3e. The best EOT-J\u3csub\u3eg\u3c/sub\u3e trade off is achieved by the laminated layers with a CeO \u3csub\u3e2\u3c/sub\u3e starting layer deposited at 520°C. copyright The Electrochemical Society.\u3c/p\u3