| A lot of investigation has been performed on hole-doped manganites with pervoskite structure in recent years, which show spectacular colossal magnetoresistance (CMR) properties. In contrast, a little work has been devoted to electron-doped manganites. However, without casual symmetry, great difference exists between hole and electron-doped manganites. For example, the properties of electron doped manganites are very sensitive to the concentration of electrons. It is essential for fundamental research and has a bright future for application. Therefore, we synthesize electron-doped manganite Pr0.1Ca0.9MnO3, adopting different sintering temperature to regulate the oxygen content and electron concentration for the first time, in order to control the properties of materials ultimately.In this paper,the crystal structure, magnetic and transport properties of Pr0.1Ca0.9MnO3 samples are systematically studied. Pr0.1Ca0.9MnO3 polycrystals which have an orthorhombic distorted perovskite structure are sintered at different temperatures. With the increase of sintering temperatures, crystal grain begins to grow up, oxygen content decreases and oxygen loss increases.Pr0.1Ca0.9MnO3 is a system where ferromagnetic and antiferromagnetic components coexist. Competition between them makes it in the state of cluster glass at low temperature. The Magnetic hysteresis loops show clear hysteresis, but come along with an obviously unsaturated moment. Besides, the obvious bifurcate behavior are shown between zero field cool (ZFC) and field cool (FC) magnezation below TC. Moreover, in the temperature dependence of ac susceptibility curves, the freezing temperature peaks shift to higher temperature and become progressively rounded with the increase of frequency.The sintering temperature rising from 800℃to 1000℃leads to more oxygen loss in Pr0.1Ca0.9MnO3, which introduces more eg electrons into these materials. eg electrons favors ferromagnetic state, so that the magnetic moment at 10 K increases. However, as sintering temperature continues to rise, more eg electrons are introduced, and when the concentration is high enough, localization of electrons appears, so that ferromagnetism is suppressed, and the magnetic moment at low temperature decreases. Consequently, for the sample synthesized at 1300℃, an obvious antiferromagnetic state emerges. These peculiar magnetic behaviors have not been reported yet.Pr0.1Ca0.9MnO3 in both zero field and an external magnetic field of 5 T exhibits semiconductive behavior over the temperature range 10 K |
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