衬底温度对Fe3N薄膜生长和磁性的影响

Effect of Substrate Temperature on Growth and Magnetic Properties of Nanocrystal Fe_3N Thin Films

采用直流磁控溅射方法,以Si(100)单晶片为衬底,在衬底温度为150～450℃的范围内得到了ε-Fe3N薄膜样品.利用XRD,SEM和VSM等表征手段,研究了衬底温度对ε-Fe3N薄膜的生长和磁性的影响.实验结果表明,随着衬底温度的升高,薄膜的生长速率、晶粒尺寸和单位质量磁化强度均增大,而矫顽力呈现先增加后减小的变化趋势,当衬底温度为350℃时,矫顽力达到最大值18.72kA/m,可以认为此时薄膜样品的晶粒尺寸接近于交换作用长度.

The nanocrystal ε-Fe3 N thin films were deposited on Si（100） substrate at different substrate temperatures of 150, 250, 350, 450 ℃ by DC magnetron sputtering. The structure, morphology and magnetic properties of the films deposited at different substrate temperature were characterized via X-ray diffraction （XRD）, scanning electron microscopy （ SEM ） and vibrating sample magnetometer （ VSM ）. The results show that ε-Fe3N has ferromagnetic properties, and its grain sizes, growth velocity and unsaturated magnetization measured at 400 kA/m field increase with increasing substrate temperature. The coercive force Hc increased to 18.72 kA/m at substrate temperature of 350 ℃ firstly, the Ho decreased with the substrate temperature increasing to 450 ℃. It can be deduced that exchange length （Lex） of nanocrystal ε-Fe3 N thin films was about grain size 30 nm.