Crystallographic and magnetic properties of a new rare‐earth iron nitride Nd_2–xSm_xFe₁₇N_y (y ∼ 3)

Abstract

The effect of nitrogen insertion on the structural and magnetic properties of Nd 2-x Sm x Fe 17 metallic alloys has been investigated. X-ray powder diffraction characterizations show that all the nitrides are single phase and crystallize in the Th 2 Zn 17 -type structure. The lattice parameters of the Nd 2-x Sm x Fe 17 N y compounds decrease with samarium content. Magnetization studies show that all the samples are ferromagnetic at room temperature. Nitrogen insertion leads to an increase of the Curie temperature T c . T c is found to increase from 370 K for NdSmFe 17 to 760 K for NdSmFe 17 N 2.8 . It leads also to an increase of the saturation magnetization M s . to 45% for x = 2. X-ray diffraction characterizations on magnetically aligned powder samples of Nd 2-x Sm x Fe 17 N y reveal a change in the easy magnetization direction from planar for x = 0 to c axis for x = 2.

Investigation of (R1−xR′x)2(Fe,Co)17 powders by Mössbauer spectrometry

“…We found that the calculated values of the magnetization are very close to the measured saturated magnetization at room temperature [12][13][14][15][16][17] when:…”

“…In the present paper, the investigations are made by varying the concentration of the rare earths in (R 1−x R x ) 2 Fe 17 and (R 1−x R x ) 2 Fe 16 Co alloys. This study follows previous research on the intrinsic magnetic properties (magnetization and Curie temperature) of the same alloys [12][13][14][15][16][17]. The local information on the Fe sites obtained by Mössbauer spectrometry is compared with previous magnetic data.…”

Structural and magnetic investigation of powders by Mössbauer spectrometry

“…The insertion of nitrogen has been carried out in static nitrogen gas under a pressure of 15 MPa at 733 K for 24 h. The nitrogen content was checked by the weight increase in the samples. It was found to be 2.9 ± 0.1 atoms per formula unit [5,6,12]. For these experiments a Brucker D8 powder diffractometer with the Co(K␣1) radiation ( = 0.1788970 nm) was used.…”

“…Nitrogenation induces a volume expansion of the lattice between 3% and 7%, leading to a large enhancement of both Curie temperature and magnetization [5,6]. Like their unnitrided counterparts, the R 2 Fe 17 N z compounds crystallize in a rhombohedral Th 2 Zn 17 structure for light rare-earths (Pr, Nd, Sm) [5,6], the nitrogen atoms being located predominantly on the 9e site [7].…”

“…The structure of the samples has been investigated by X-ray diffraction. Magnetic measurements have been previously done on the same samples to determine Curie temperature and saturation magnetization [5,6,12].…”