退火气氛对Mn掺杂钛酸锶钡薄膜的影响

The Effect of Annealing Atmosphere on Mn-doped Barium Strontium Titanate Thin Films

采用金属有机物分解法制备了(Ba_(0.95)Mn_(0.05))_(0.4)Sr_(0.6)TiO_3薄膜,比较了两种退火气氛对样品的微观特性及磁性能的影响。XRD和AFM测试结果表明两种薄膜均为标准的钙钛矿结构,氧气退火样品具有更好的a轴取向和更大的晶粒度。磁性测量发现两种样品都有自旋玻璃行为,并且氮气退火样品的矫顽场和饱和磁矩都大于氧气退火样品,具有软磁特征。分析表明样品的磁性可能来源于Mn离子之间的交换作用以及束缚磁极化子的交换作用,而铁磁与反铁磁的竞争失措则导致了自旋玻璃转变。

（Ba0.95Mn0.05）0.4Sr0.6TiO3 thin films are prepared by MOD. The effects of two annealing atmospheres on the microscopic and magnetic properties of the samples are compared. The results of XRD and AFM show that the two films both have the standard perovskite structure, and the oxygen annealed sample has a better a-axis orientation and larger grain size. The magnetic measurements display that both of the two samples have spin glass behavior. The coercive field and saturated magnetic moment of the nitrogen annealed sample are larger than those of the oxygen annealed sample, which displays soft magnetic characteristic. The analysis indicates that the magnetism of the samples may be due to the exchange interaction between the Mn ions and that of the bound magnetopolarons, while the competition between the ferromagnetic and antiferromagnetic interactions would result in the spin glass.