The influence of static electric field on the transport properties in La 0.7 A 0.3 MnO 3 ͑A =Ca,Ba͒ epitaxial thin films was investigated by using field effect configurations ͑FEC͒. A single layer manganite film was deposited on LaAlO 3 ͑LAO͒ substrate by pulsed laser deposition technique, and then a simple FEC was formed on it using the lithography technique, in which the manganite film was used as a channel, and the LAO substrate as a gate. Surprising results were achieved by employing such a FEC. The transport resistance increases with a positive gate voltage but decreases with a negative bias, which means the electroresistance ͑ER͒ effect changes sign with the field direction. The observed reduction of resistivity for the La 0.7 Ca 0.3 MnO 3 and La 0.7 Ba 0.3 MnO 3 channels reaches ϳ32% and ϳ34% upon a bias of −80 and −300 V, respectively. The films could completely return to their pristine state after the bias was removed and the ER effect could be fully reproduced.

Articles you may be interested inCurrent-sensitive electroresistance and the response to a magnetic field in La 0.8 Ca 0.2 MnO 3 epitaxial thin films J. Appl. Phys. 97, 10H706 (2005); 10.1063/1.1847092 Current-induced electroresistive effect in mixed-phase La 0.67 Ca 0.33 MnO 3 thin films Appl. Phys. Lett. 85, 6194 (2004); 10.1063/1.1840114 Current-induced effect on the resistivity of epitaxial thin films of La 0.7 Ca 0.3 MnO 3 and La 0.85 Ba 0.15 MnO 3

The transport behavior of La 0.8 Ca 0.2 MnO 3 thin films with Curie temperature T C at ϳ286 K has been investigated under various applied currents in the absence of magnetic field. An unusual current-induced electroresistance (ER) was observed. When the applied current density reaches a critical value, the films could not revert to the initial state. A novel state can be induced by a suitable large current, in which the insulation-metal transition temperature remains almost unchanged comparing with the initial state, whereas the value of the peak resistance is very sensitive to the applied current. Even a rather low current density can depress it significantly. ER reaches ϳ43% under a small current of 0.5 mA (density ϳ1 ϫ 10 4 A cm −2). The observed ER effect seems to favor a percolative phase separation picture.

Removable partial dentures (RPDs) are used to restore missing teeth and are traditionally fabricated using the lost-wax casting technique. The casting process is arduous, time-consuming, and requires a skilled technician. The development of intraoral scanning and 3D printing technology has made rapid prototyping of the RPD more achievable. This article reports a completed case of direct fabrication of a maxillary RPD metal framework (Kennedy Class I) using intraoral scanning and 3D printing techniques. Acceptable fit and satisfactory clinical outcome were demonstrated. Intraoral scanning and 3D printing for fabrication of the RPD metal framework is a useful alternative to conventional impression and casting techniques, especially for patients suffering from nasal obstruction or intolerance.

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