Presence of a paramagnetic phase well below the ferromagnetic onset in La0.67-xBixCa0.33MnO3

Abstract

Partial replacement of by in depresses the ferromagnetic order of the compound and leads to a stepwise magnetic behavior characterized by two subsequent transitions at and . Based on a combined study of the electron spin resonance spectra and the thermal and isothermal magnetization, a complete scenario for the phase separation that causes the complex behavior has been given. It is found that the paramagnetic phase exists in a wide temperature region even below the ferromagnetic onset at . It coexists with the ferromagnetic phase below and with both the ferromagnetic and antiferromagnetic phases below with a reduced but significant fraction. The magnetization jump at is possibly a conversion of the remaining paramagnetic phase into the ferromagnetic phase.