Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Grain size-dependent magnetic and electric properties in nanosized YMnO3 multiferroic ceramics | Han et al. Nanoscale Research Letters 2011 6 201 http content 6 1 201 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Grain size-dependent magnetic and electric properties in nanosized YMnO3 multiferroic ceramics Tai-Chun Han Wei-Lun Hsu Wei-Da Lee Abstract Magnetic and electric properties are investigated for the nanosized YMnO3 samples with different grain sizes 25 nm to 200 nm synthesized by a modified Pechini method. It shows that magnetic and electric properties are strongly dependent on the grain size. The magnetic characterization indicates that with increasing grain size the antiferromagnetic AFM transition temperature increases from 52 to 74 K. A corresponding shift of the dielectric anomaly is observed indicating a strong correlation between the electric polarization and the magnetic ordering. Further analysis suggests that the rising of AFM transition temperature with increasing grain size should be from the structural origin in which the strength of AFM interaction as well as the electrical polarization is dependent on the in-plane lattice parameters. Furthermore among all samples the sample with grain size of 95 nm is found to have the smallest leakage current density 1 pA cm2 . PACS . t Introduction The hexagonal RMnO3 R rare earth element or Y compounds present opportunities for the industrial applications due to their unique nature of multiferroism 1 . Namely the ferromagnetism ferroelectricity and ferroelasticity occur simultaneously in the same material. The characteristics of multiferroism include a spontaneous magnetization which can be switched by an applied electric field a spontaneous electrical polarization which can be reoriented by an applied magnetic field and a strong coupling between these two properties 2 . Owing to the coupling between ferroelectric and magnetic domains multiferroism is likely to offer a whole range of new applications and phenomena.
