Chemical Diversity in View of Property Generation by a New Combinatorial Approach

Abstract

Even the exploration of the phase space given by a large number N (N ≤ 61) of components but a limited number q (q ≤ 6) of elements Ei in e.g. metal oxides Ex1>(1)Ex2(2)…Exq(q)Oy is a demanding task and needs a combinatorial approach which, by setting up starting conditions for solid‐state reactions, is taking favour of efficient combinatorial functions. Estimations showed that within a single sample prepared by mixing N starting components, the number of local reaction centres (configurations) is exceeding the number of phase systems. A huge amount of about 1012 starting grains for a sample of one cm3 provides population of each configuration many times. The distribution for the grain size and the number of grains building up a configuration allow to explore compositional fields in phase diagrams of the order q. The single sample concept (SSC) is particularly of interest for property oriented syntheses, where e.g. magnetic materials are produced in minor quantities. Magnetic chromatography is applied to extract ferromagnetic materials formed by the SSC. A horizontal separator is presented and applied to extract new ferromagnetic Fe‐based oxides from SSC reaction mixtures.

Observation of high-Tc superconductivity in inhomogeneous combinatorial ceramics

“…It was challenging to measure the magnitude of the susceptibility at a particular sample point and temperature. This was due to a combination of several factors: First, we used a relatively small area pickup loop for these measurements to get good spatial 7 resolution. This means that errors in the spacing between the sample and the sensor produced large variations in the diamagnetic signal observed.…”

Superconducting phase formation in random neck syntheses: a study of the Y–Ba–Cu–O system by magneto-optics and magnetometry

“…Recently, a combinatorial approach for searching new oxide superconductors was presented [1,2,3,4]. The basic idea is to generate most inhomogenously reacted ceramic samples in order to synthesize new superconducting compounds [1,2,3]. Starting with a mixture of grains of several initial components, due to their statistical distribution, various combinations of original grains are created in different parts of a sample.…”

The energy landscape concept and its implications for synthesis planning

“…Further arguments against accessibility of high component systems claim that it is impossible to force more than about seven different elements into one individual solid compound, via conventional all-solid-state reaction routes [2,3]. The intricacies to be managed at running such reactions, in particular in a reproducible fashion, are well recognized [4].…”