The Micro-structure And Magnetic Properties Of Fe-Ga Thin Films With Different Preparation

This paper present a study of the growth and magnetic properties of Fe-Ga thin filmsdeposited on Si(100) substrates and by the dc magnetron sputtering method with variousdeposition parameters. The structure and magnetic properties of Fe-Ga thin films have beeninvestigated by using X-ray diffraction analysis (XRD), scanning electron microscope (SEM),physical property measurement system (PPMS). The influences of the deposition parameterssuch as sputtering power, substrate’s temperature and sputtering duration on the micro-structureand magnetic properties of Fe-Ga thin films were discussed.XRD results show that all samples exhibited a (110) disordered bcc structure with a phasestructure of A2. The crystallite size increases with increase in the sputtering power, a moderatesputtering power will be conducive to a better crystallization. When raise the substrate’stemperature, the Fe-Ga film’s crystallite size is significantly larger and contributes to bettercrystallization. Also, increasing the sputtering duration is helpful to Fe-Ga thin films’crystallization within a certain range.The EDS analyses show that the composition of the Fe-Ga thin films is nearly as the targetcomposition Fe83Ga17. SEM results indicate that the grain size of Fe-Ga films increases with theincreasing in the sputtering power, which tends to be not so obvious when the substrate’stemperature is high. Within the substrates’ temperatures raising range from room temperature to250℃, the films’ grain sizes increased significantly. While at the substrate’s temperature of350℃, films’ growth pattern has changed from columnar growthing. Also, increasing thesputtering duration colud enlarge the grain sizes of Fe-Ga films samples within a certain range.The magnetic property measurement indicates that all Fe-Ga thin films demonstrating atypical ferromagnetism, additional, the films sputtering at temperatures of150℃,200℃and250℃definitely show soft magnetic properties which exhibite the coercivity Hcof about40Oe,the saturation field of about100~200Oe, the remanence ratio Mr/Msof more than0.9. With theraising of sputtering power, films’ coercivity Hctends to be decreased, the remanent magnetization Mrand the saturation magnetization Msgradually decreased, the remanence ratioMr/Msdecreased slowly. However, as the substrate’s temperature increases, the coercivity Hcdecreases first, then increases, while the remanence ratio Mr/Msgoes a opposite way. Whenincreasing the sputtering duration, the remanent magnetization Mrand the saturationmagnetization Mstend to be decreased while the coercivity Hcand the remanence ratio Mr/Msbasically unchanged.