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-δ and (La1-xSrx)MnO3-δ single crystals were studied as a function of the dopant concentration x and the oxygen deficiency δ. Crystals were grown by the floating zone process and subjected to post-annealing treatments in oxidizing or reducing atmosphere to control δ. This two-step process allows the precise control of δ. Moreover, a wide range of δ values not attainable by changing only the growth conditions can thus be studied. Controlling the Fe and Mn valencies via the oxygen deficiency was found to affect the magnetic and electrical properties profoundly.