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We report measurements of the low-frequency optical response in epitaxial thin films of La0.67Ca0.33MnO3 in the temperature range covering both the ferromagnetic metallic state and the paramagnetic insulating state. We observe a bolometric optical response in fully oxygenated films of the above composition as well as in oxygen deficient films. In both types of samples, the optical response is thermal in nature as indicated by its proportionality with the temperature derivative of the resistance dR/dT.

Interactions of excited activators in rare earth and transition metal doped phosphors and their role in low energy cathodoluminescence J. Appl. Phys. 91, 153 (2002);

We present a laser-based direct write technique termed matrix-assisted pulsed-laser evaporation direct write (MAPLE DW). This technique utilizes a laser transparent fused silica disc coated on one side with a composite matrix consisting of the material to be deposited mixed with a laser absorbing polymer. Absorption of laser radiation results in the decomposition of the polymer, which aids in transferring the solute to an acceptor substrate placed parallel to the matrix surface. Using MAPLE DW, complex patterns consisting of metal powders, ceramic powders, and polymer composites were transferred onto the surfaces of various types of substrates with <10 micron resolution at room temperature and at atmospheric pressure without the use of masks.Current trends for developing advanced electronic and sensor systems place great emphasis in achieving performance levels generally associated with integrated circuits. This requires further miniaturization, while enhancing the functionality and reliability of existing systems. New strategies are needed in order to eliminate the long lead times required for the fabrication of prototypes and evaluation of new materials and designs. The use of rapid prototyping techniques such as direct write, which do not need photolithographic processing, provide a solution to the above requirements. Direct write technologies do not compete with photolithography for size and scale but rather add a complementary tool for specific applications requiring rapid turnaround and/or pattern iteration, conformal patterning, or modeling difficult circuits. Examples of direct write technologies for fabricating or modifying metallic interconnects and/or other electronic passive elements include ink jet printing, 1 direct write of ceramic slurries (Micropen), 2 laser trimming, 3 and laser chemical vapor deposition (LCVD). 4 However, none of these techniques is capable of operating in air and at room temperature while maintaining sub-10-m resolution and without requiring ex situ processing, as well as being compatible with the broad classes of materials needed for electronic and sensor systems.Over the past decade, various laser-based direct write techniques have been developed for depositing different types of materials. Laser ablation transfer (LAT) has been used to generate high-resolution color images by means of laser transferring pigments of different colors for printing applications. 5 Similarly, laser-induced forward transfer (LIFT) has shown the ability to direct write metals for interconnects and for mask repair and also simple dielectric materials such as metal oxides. 6,7 LIFT is a technique that employs a focused pulsed laser beam to vaporize a thin film from a laser transparent donor substrate in air and at room temperature. 8 The material then condenses onto an acceptor substrate placed in close proximity (25-50 m) to the donor substrate. The area coated per laser pulse depends on the size of the laser spot striking the film as well as the gap between both substrates. However, because LIFT ...

We report measurements of 1/f electrical noise in two hole doped manganite perovskite oxides, La 0.67 Ca 0.33 MnO 3 and Pr 0.67 Sr 0.33 MnO 3 , which exhibit colossal magnetoresistance. The noise magnitude represented by the Hooge parameter is nearly 8 orders of magnitude larger than that observed in ordinary metals ͑and semiconductors͒ and nearly 5-6 orders of magnitude larger than that observed in epitaxial films of the perovskite oxide YBa 2 Cu 3 O 7 in the normal state. The normalized noise spectral density increases with decreasing temperature below the resistivity peak, suggestive of the presence of additional low energy noise processes in the ferromagnetic metallic state.

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A novel laser-based direct-write technique, called Matrix Assisted Pulsed Laser Evaporation Direct Write (MAPLE-DW), has been developed for the rapid prototyping of electronic devices. MAPLE-DW is a maskless deposition process operating under ambient conditions which allows for the rapid fabrication of complex patterns of electronic materials. The technique utilizes a laser transparent substrate with one side coated with a matrix of the materials of interest mixed with an organic vehicle.The laser is focussed through the transparent substrate onto the matrix coating which aids in transferring the materials of interest to an acceptor substrate placed parallel to the matrix surface.With MAPLE-DW, diverse materials including metals, dielectrics, ferroelectrics, ferrites and polymers have been transferred onto various acceptor substrates. The capability for laser-modifying the surface of the acceptor substrate and laser-post-processing the transferred material has been demonstrated as well. This simple yet powerful technique has been used to fabricate passive thin film electronic components such as resistors, capacitors and metal lines with good functional properties. An overview of these key results along with a discussion of their materials and properties characterization will be presented.Keywords: direct vvrite, laser forward transfer, matrix assisted pulsed laser evaporation (MAPLE), matrix assisted pulsed laser evaporation direct write (MAPLE-DW), rapid prototyping, electronics devices.