HIGH COERCIVITY SM2FE17NX AND RELATED PHASES IN SPUTTERED FILM SAMPLES

High coercivity film samples of the ordered Sm2Fe17Nx phase with intri nsic coercivities, (i)H(c) up to 23 kOe at 293 K, and 35 kOe at 10 K, were synthesized by rf sputtering. Random orientation Sm2Fe17 films we re formed by the subsequent crystallization of originally amorphous de posits. The (i)H(c) of the original Sm2Fe17 films was 0.75 kOe at 293 K. X-ray diffractometer traces from 2theta = 28-degrees to 73-degrees, Cu(Kalpha), exhibited 14 lines. Before nitriding all 14 lines were fi t to the 2-17 rhombohedral structure with a = 8.555 angstrom, c = 12.4 45 angstrom, with a weighted root-mean-square deviation in 2theta of 0 .01-degrees. After nitriding the cell volume increase was almost-equal -to 7%. Nitriding of the ordered 2-17 films had to be performed in a v ery narrow temperature range to optimize the magnetic properties. The best magnetic properties were obtained by crystallizing the amorphous deposits in situ at a temperature of almost-equal-to 900 K for 1 h and then subsequently nitriding in N2 gas at 0.75 atm., at 675-725 K, for 2 h. The room temperature coercivity as a function of the Sm concentr ation reached a maximum value of almost-equal-to 23 kOe at a slightly richer than stoichiometric Sm composition.