Comparison of the magnetic and transport properties of Ga-, Ni-, and Fe-doped perovskite manganese oxides

A comparative study on magnetic and transport properties has been performed for B-site substituted perovskites La0.67Sr0.33Mn0.90B0.10O3 (B = Ga, Ni, and Fe). The doped samples show a notable decrease of the Curie Temperature, from 365 K of the undoped sample to 290 K (Ga), 292 K (Ni), and 265 K (Fe). Furthermore, the metal-semiconductor transition peaks in the doped samples shift to lower temperature, from above 300 K (undoped) to 212 K (Ga), 237 K (Ni), and 195 K (Fe). This considerable differences in magnetic and transport properties between doped and undoped samples and the diversity among the doped samples can be explained by the destruction of the partial double-exchange interactions and the exchange couplings between Mn and doped ions. (C) 1999 American Institute of Physics. [S0021-8979(99)04420-5].