EPITAXIALLY GROWN FE16N2 SINGLE-CRYSTAL FILMS WITH HIGH SATURATION MAGNETIZATION PREPARED BY FACING TARGETS SPUTTERING

摘要

alpha''-Fe16N2 single-crystal films were prepared with a facing targets sputtering (FTS) system onto single-crystal NaCl substrates, at a deposition rate as high as 2.0 Angstrom s(-1). In the process of deposition, the partial pressures of argon and nitrogen gases were held at 0.3 Pa and 0.05 Pa, respectively. The effect of the substrate temperature on the formation of Fe-N phases was investigated in detail. The crystal structure of the Fe-N films was examined with an x-ray diffractometer and a transmission electron microscope. At T-s = 150 degrees C, single-crystal alpha''-Fe16N2 grows epitaxially on (alpha-Fe with an orientation relationship of alpha''-Fe16N2 (110)//alpha-Fe (110), Fe16N2 [(1) over bar 11] //alpha-Fe[(1) over bar 11]. When T-s = 100 degrees C and 200 degrees C, the Fe-N films contain more alpha'-martensite and gamma'-Fe4N, respectively. The integrated electron diffraction pattern of the alpha''-Fe16N2 single crystal in the [(1) over bar 11] direction was dearly observed. The film revealing a single-crystal electron diffraction pattern exhibits a high saturation magnetization M(s) up to 2050 emu cc(-1), and this confirms the high M, of the alpha''-Fe16N2 phase. [References: 22]