强磁场下Sm-Fe薄膜不同晶态组织演化及磁性能调控

Evolutions of different crystalline textures in Sm-Fe film fabricated under high magnetic field and subsequent tuning magnetic properties

针对Sm-Fe薄膜的不同晶态组织演化和磁性能调控问题,采用分子束气相沉积方法制备Sm-Fe薄膜时,通过改变Sm含量、膜厚和强磁场来调节薄膜的晶态和磁性能.结果表明,Sm含量可以调节Sm-Fe薄膜的晶态组织演化,而晶态组织的演化和强磁场对磁性能有显著影响.Sm-Fe薄膜在Sm原子比为5.8%时是体心立方晶态组织,在Sm含量为33.0%时为非晶态组织,而膜厚和强磁场不会影响薄膜的晶态组织.非晶态薄膜的表面粗糙度和表面颗粒尺寸都比晶态薄膜的小,施加6 T强磁场会使表面颗粒尺寸增大,而表面粗糙度降低.非晶态薄膜的饱和磁化强度M_s比晶态薄膜的M_s(1466 emu/cm^3,1 emu/cm^3=4π×10-10T)低约47.6%,施加6 T强磁场使非晶态和晶态薄膜的M_s均降低约50%.Sm-Fe薄膜的矫顽力H_c在6—130 Oe(1 Oe=103/(4π)A/m)之间,其中,非晶态薄膜的H_c比晶态薄膜的H_c大.施加6 T强磁场使晶态薄膜的H_c增大,而使非晶态薄膜的H_c减小,最高可以减少95%.结果表明含量和强磁场可以用于调控Sm-Fe薄膜的晶态和磁性能.

In order to tune the crystalline texture evolution and magnetic properties of the Sm-Fe film, molecular beam vapor deposition method is used to fabricate the Sm-Fe films. Sm content, thickness, and high magnetic field are used to affect the crystalline texture and magnetic properties. X-ray diffraction is used to analyze the texture evolution. Atomic force microscope is used to observe the surface morphology and roughness. Energy-dispersive X-ray spectroscopy is used to measure the compositions of the film. Vibrating sample magnetometer is used to test the magnetic properties. The results show that the crystalline textures are tuned through the Sm content. The crystalline texture evolution and high magnetic field have significant effect on the magnetic properties of the Sm-Fe film. The Sm-Fe film with 5.8% atomic content is of bcc crystal structure and is of amorphous structure with 33.0% Sm. Neither the thickness nor the high magnetic field has an influence on the crystalline texture. The surface roughness and particle size on the surface of the amorphous film are smaller than those of the crystal film. A 6 T high magnetic field increases the surface particle size and reduces the surface roughness. Saturation magnetization Ms of the amorphous film is 47.6% lower than that of the crystal film （1466 emu/cm3, 1 emu/cm3=4π × 10^-10 T）. The 6 T high magnetic field reduces the Ms of crystal and amorphous film by about 50%. The coercivity Hc values of the Sm-Fe films are in a range of 6-130 Oe （10e = 10^3/（4π） A/m）. The Hc of the amorphous film is higher than that of the crystal film. The 6 T high magnetic field increases the Hc of the crystal film and reduces the He of the amorphous film. The highest reduction is 95%. The anisotropy of the crystal film transforms to isotropy of the amorphous film. High magnetic field increases the anisotropy of the crystal film. The squareness of the crystal film is much higher than that of the amorphous film. High magnetic field has a significant effect on the measured magnetic field to obtain saturation magnetization in the film. This measured saturation magnetic field increases in the amorphous film and decreases in the crystal film after the high magnetic field has been exerted during the film growth. These results indicate that the Sm content and high magnetic field can be used to tune the crystal textures and magnetic properties of the Sm-Fe films.