A Class of Cobalt Oxide Magnetoresistance Materials Discovered with Combinatorial Synthesis

Abstract

The recent development of methods for generating libraries of solid-state compounds has made it possible to apply combinatorial approaches to the discovery of materials. A library of 128 members containing different compositions and stoichiometries of Ln x M y CoO δ , where Ln = Y or La and M = Pb, Ca, Sr, or Ba, was synthesized by a combination of thin-film deposition and physical masking techniques. Large magnetoresistance has been found in La x (Ba,Sr,Ca) y -CoO δ samples, whereas Y-based samples exhibit much smaller magnetoresistive effects. The magnetoresistance of the Co-containing compounds increases as the size of the alkaline earth ion increases, in sharp contrast to Mn-containing compounds, in which the magnetoresistance effect increases as the size of the alkaline earth ion decreases.

Combinatorial approach for ferroelectric material libraries prepared by liquid source misted chemical deposition method

“…These methods are considered to be very efficient and quickly provide us the quantitative activity structure relationship to establish the criteria for designing novel functional materials, which have been extensively used for the discovery of functional electronic thin film materials, novel polymers, and catalysts since the mid-1990s (1)(2)(3)(4)(5)(6)(7)(8)(9)(10).…”

“…Bismuth layered perovskite ferroelectric films, SrBi 2 Ta 2 O 9 (24) and (Bi,La) 4 Ti 3 O 12 (BLT) (25), have drawn an interest for ferroelectric random-access memory because of the fatigue-free properties over 10 10 read/write cycles, unlike Pb(Zr,Ti)O 3 (PZT) (26,27 with BLT powder showed that 2P r was maximum when the Bi/La was 3.75/0.25 (33)(34)(35).…”

“…Thin-film libraries containing various compositions were fabricated by adopting multimask techniques (3)(4)(5)(6). Ten binary masks or five quaternary masks should be used to prepare 1,024 (2 10 ) different samples on a wafer.…”

Microfabrication, Microstructures and Microsystems

“…Microstructures should also provide the opportunity to study basic scientific phenomena that occur at small dimensions: one example is quantum confinement observed in nanostructures [1].Although microfabrication has its basis in microelectronics and most research in microfabrication has been focused on microelectronic devices [2], applications in other areas are rapidly emerging. These include systems for microanalysis [3 -6], micro-volume reactors [7,8], combinatorial synthesis [9], microelectromechanical systems (MEMS) [10, 1l], and optical comPonents [r2-r41.…”

“…Most are fabricated from silicon using standard microlithographic techniques (silicon bulk micromachining and polysilicon surface micromachining) 144-461. With these methods, thousands of mechanical elements (for example, cantilevered beams, springs,linkages, mass elements and joints) can be batch-fabricated on a single silicon substrate [9,11]. Microactuators, micromotors and microengines [46] have been fabricated for optical switches, fluid pumps [a7], systems for drug delivery and microchemical analysis and high-speed rotational gyros for navigation [48][49][50][51].More recently, surface micromachining techniques have been used to fabricate miniaturized optical components [12][13][14].…”