Structural and magnetic properties of electron-doped manganites La0.85Te0.15Mn1-xCuxO3 (0≤x≤0.20)

The effects of Cu doping at the Mn site on the structural and the magnetic properties of electron-doped manganites La0.85Te0.15Mn1-xCuxO3 (0≤x≤0.20) have been studied. The structural parameters were obtained by fitting the XRD data with space group R anti 3c by the Rietveld method. Upon cooling, all the samples undergo the paramagnetic-ferromagnetic phase transition. The magnetization measurements under an applied field of 0.1 and 4.5 T show that the Curie temperature TC decreases with increasing the Cu-doping level, whereas the magnitude of magnetization at low temperatures increases as the Cu content increases from x=0 to 0.10 but decreases when x>0.10. We consider that these interesting phenomena are intrinsic. The results can be understood by the opening of new double-exchange channel between Mn3+-O-Mn4+ due to the introduction of Mn4+ ion caused by the substitution of Cu2+ for Mn3+. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)