Spin glass behavior in hole- and electron-doped bismuth manganite single crystals

The hole- and electron-doped bismuth manganites Bi0.55Ca0.45MnO3, Bi0.55Sr0.45MnO3 and Bi0.95Ce0.05MnO3 single crystals were grown using the flux-growth method. Their structural, magnetic and electrical transport properties have been compared studied. All samples show spin-glass magnetic behavior at low temperatures. In the immediate temperature region, an antiferromagnetic transition at TA and a charge-ordering state at TCO are observed for Bi0.55Ca0.45MnO3 crystal, whereas only an antiferromagnetic transition exists in Bi0.95Ce0.05MnO3 and Bi0.55Sr0.45MnO3 crystals. Bi0.55Ca0.45MnO3 and Bi0.55Sr0.45MnO3 samples show semiconducting transport behavior in the whole studied temperature range, whereas Bi0.95Ce0.05MnO3 is an insulator at room temperature. In addition, near TCO a positive magnetoresistance as large as 70.7% is observed for Bi0.55Ca0.45MnO3 sample under 5 T applied magnetic field. The obtained results may originate from the rotation of the polarized Bi-6s2 lone pair electrons in the magnetic field.