局域结构畸变对Co2FeAl0.5Si0.5合金薄膜中磁有序的影响

series of Heusler alloy Co2FeAl0.5Si0.5 (CFAS) thin film on MgO(100) substrate have been fabricated by magnetron sputtering with In-situ annealing process at temperature (350oC, 450oC, 550oC and 650oC), respectively. XRD, temperature-dependent Raman and SQUID measurements have been performed to clarify the interplay between the structure and magnetic properties of the CFAS films. The XRD results reveal that both the crystallization and chemical ordering of the CFAS films are enhanced by the increasing annealing temperature. From the Raman spectroscopy, the representative Raman-active modes associated with L2 phase can be observed. The Raman mode at 843 cm-1 shows strong temperature dependence behavior, which has an obvious increase in intensity with the increasing of the annealing tempertuare as well. On the other hand, the increasing saturation magnetization and decreasing coercivity of the CFAS films with the increasing annealing temperature can be found by the SQUID measurement. These structural and magnetic results of the CFAS films demonstrate the crystallization and chemical ordering play an important role in the magnetic property. However, the variation of the Raman mode suggests that the local lattice distortion associated with the L21 phase can not be considered as the origin of the magnetic disordering.