Doping at the Mn site of the electron-doped manganite Ca0.9Ce0.1MnO

The effects of substitution of chromium and ruthenium for manganese on the magnetic and transport properties of electron-doped manganite Ca0.9Ce0.1MnO3, with d(z)(2) orbital-ordered and the associated antiferromagnetic (AFM) characters, have been studied. As expected, due to the participation of the Cr3+ (t(2g)(3) e(g)(0)) and Ru4+/5+[t(2g)(4) e(g)(0)/t(2g)(3) e(g)(0))] ions in the e(g) band broadening for the Mn3+ (t(2g)(3) e(g)(1)) and Mn4+ (t(2g)(3) e(g)(0)) species, the suppression of the AFM transition by Ru and Cr doping is accompanied by an increase in the ferromagnetic (FM) character. The coexistence of FM and AFM phases in these Ru- and Cr-substituted compounds leads to the observations of cluster glass behaviour, the giant magneto-resistive memory (GMM) effect and other magnetic-history-dependent magnetic and transport properties. Our observation of the GMM effect in these Cr- and Ru-doped compounds is the first of its kind in the magnetically phase-separated bulk polycrystalline compounds.