高压处理对稀磁半导体Zn_(1-x)Mn_xO磁性的影响

用固相反应法制备出过渡金属Mn掺杂的ZnO系列样品,并对其进行了高压处理.高压处理后的样品,通过扫描电子显微镜和X射线衍射仪进行了微观结构的表征分析.通过磁性能的测量,初步研究了压力对Mn掺杂ZnO稀磁半导体磁性能的影响.结果表明:适当的高压处理可以有效增强材料的室温铁磁性,但当压力超过一定值后,压力会使材料的磁性能下降.     

生物合成高能化学物质

从分子到细胞,从个体到社会,能量的需求和转化无处不在。探索高能物质的合成与利用,具有较重要的科学意义和应用价值。目前高能物质的化学合成通常污染较大、耗能较高,且往往副产物较多,难以分离纯化。相较于传统的化学合成方法,生物合成具有绿色环保和高效利用清洁能源等特点,是符合国家“碳中和”目标的新型合成路径。高能物质的生物合成,将是未来的迅速发展方向之一。本文将从能源物质、含能材料和天然高能物质三个方面,选取四种代表性高能物质,介绍其生物合成途径及与之相关的关键金属酶。     

Multiferroic properties and exchange bias in Bi1-xSrxFeO3 （x = 0-0.6） ceramics

Multiferroic properties and exchange bias(EB) in Bi1-xSrxFeO3(x = 0–0.6) ceramics synthesized by a modified Pechini method are investigated. Sr concentration dependence of structure distorting, ferroelectric properties, and dielectric properties were studied at room temperature. Appropriate Sr doping(x = 0.05–0.2) has been found to decrease the conductivity, enhance ferroelectric properties and give rise to high dielectric constant. Compared with antiferromagnetic BiFeO3 compound, BSFO-x(0 ≤ x ≤ 0.4) ceramics show weak ferromagnetism at room temperature, and their exchange bias field and vertical magnetization shift are observed and exhibit a strong dependence on the content of Sr. This observed EB effect which keeps stable in BSFO ceramics at 10 K tend to vanish at room temperature with Sr concentration over 0.4.