摘要
采用水热法合成了La0.7Ca0.21Ba0.09MnO3化合物.用X射线衍射表征材料的相组成,用扫描电镜(SEM)观测样品形貌,用直接法测量材料的绝热温度(ΔTad).研究发现:水热合成钙钛矿样品时,碱度、水热温度对矿物成分有很大影响,进而影响到产物的磁热效应.而且这两大主要因素对矿物成分的影响不是彼此孤立的,而是综合性的.碱度为6 mol.L-1、水热温度为260℃的水热条件下合成了室温下的La0.7Ca0.21Ba0.09MnO3磁致冷材料,其居里温度为290 K,最大绝热磁温变为0.20 K.
La0.7Ca0.21Ba0.09MnO3 perovskite material was synthesized by hydrothermal method, the structure of which was characterized by using X-ray diffraction （XRD） and the shape was observed with SEM and the adiabatic temperature changes （△Tad） were determined directly. The experiment shows that the alkalinity and hydrothermal temperature have a great effect on the mineral composition, which then affects the magneto-caloric effect of La0.7Ca0.21Ba0.09MnO3 powders. In addition, the effect of alkalinity and hydrothermal temperature on mineral composition are not isolated but integrated. The room-temperature magnetic refrigerant material La0.7Ca0.21Ba0.09MnO3 perovskite powder was synthesized under the condition that alkalinity is 6 mol·L^-1 and hydrothermal temperature is 260 ℃. The Curie temperature of this powder is 290 K and its maximum adiabatic temperature change is 0.20 K.
出处
《内蒙古科技大学学报》
CAS
2007年第1期26-28,共3页
Journal of Inner Mongolia University of Science and Technology
关键词
水热合成
钙钛矿
磁热效应
hydrothermal synthesis
perovskite
magneto-caloric effect
