Influence of oxygen stoichiometry on electrical transport and magnetic properties of doped perovskite-type ferrate and manganate single crystals

The electrical transport and magnetic properties of (La1-xSrx)FeO3-delta an d (La1-xSrx)MnO3-delta single crystals were studied as a function of the do pant concentration x and the oxygen deficiency delta. Crystals were grown b y the floating zone process and subjected to post-annealing treatments in o xidizing or reducing atmosphere to control delta. This two-step process all ows the precise control of delta. Moreover, a wide range of delta values no t attainable by changing only the growth conditions can thus be studied. Co ntrolling the Fe and Mn valencies via the oxygen deficiency was found to af fect the magnetic and electrical properties profoundly. (C) 1999 Elsevier S cience Limited. All rights reserved.