Electron-doped colossal magnetoresistance in the sintered La1-xTxMnO3 lanthanum-deficient phase

Tetravalent doped La0.7Ce0.3MnO3 (LCeMO) and La0.8Te0.3MnO3 (LTeMO) compounds are reported as an electron-doped colossal magnetoresistance (CMR) material, with the former containing multiphases of n-type LCeMO, CeO2, and Mn-O, while the latter exhibits a single phase. We reproduced these compounds both by using previously reported processes and by other routes. The energy dispersion spectroscopy measurement in this study shows that the La0.85Ce0.017MnO3+delta and La0.9MnO3+delta are the main phases in both LCeMO and LTeMO bulk solid material, respectively, neither of which have the claimed n-type LCeMO and LTeMO phases. This finding is further corroborated by the XRD data analysis results. Similar properties can also be found in La1-xSnxMnO3+delta and La1-xZrxMnO+delta systems. The present study casts doubt on the interpretation of n-type electronic property in bulk solid of LCeMO and LTeMO, and proposes that the n-type CMR may be formed in the metastable state.