【摘要】 运用激光超声的方法测定了五种不同掺杂的巨磁锰氧化物La0.7Ca0.3Mn1-xCrxO3(0.01≤x≤0.60)室温(300K)下的超声纵波声速.结合热导率的数据,对声速随掺杂浓度的变化原因进行了深入的分析.得到在顺磁绝缘态Cr3+离子的掺入造成了晶格局部涨落的变化,低掺杂使得晶格局部涨落增强,声子U散射弛豫时间减小.更多还原

【Abstract】 The ultrasonic velocities of Cr doped polycrystalline samples La0.7Ca0.3Mn1-xCrxO3(0.01≤x≤0.60)were measured under the temperature 300K by means of laser ultrasonic technology. Combining with data of thermal conductivity, we analyzed in detail the reasons of ultrasonic velocity abnormity as the doped concentration changed. The local lattice fluctuation changes as the Cr content is increased, and is enhanced when doping at low level. Consequently, there is a decrease in the relaxation time of phonon-U-scattering.更多还原