The effect of deficit of strontium on structural, magnetic and electrical properties of La0.8Sr0.2−x□xMnO3 manganites

A systematic study of physical properties of the defective manganites La0.8Sr0.2-x□xMnO3 (0≤x≤0.2) was carried out. The powdered samples have been prepared by the conventional ceramic method at 1673 K. The structural, magnetic and electrical properties of these compounds with the varied Mn3+/Mn4+ ratio are studied. These compounds crystallize in a rhombohedral (R3¯c) structure and exhibit a paramagnetic-semiconductor to ferromagnetic-metallic transition with decreasing temperature. The Curie temperature TC decreases from 294 K to 209 K with increasing vacancy content. The resistivity transition temperature TP decreases from 260 K to 190 K as Sr content decreases.