PROBLEM TO BE SOLVED: To provide a samarium-iron-nitrogen based sintered magnet which includes crystal grains pulverized to a size close to a grain size of a single magnetic domain, and is superior in coercive force.

SOLUTION: A samarium-iron-nitrogen based sintered magnet is provided, which comprises a samarium-iron-nitrogen based alloy, where crystal grains included therein are larger than 0.04 μm and 5 μm or less in average grain diameter, and which has an oxygen content of 0.7 wt% or less. Also, a samarium-iron-nitrogen based sintered magnet is provided, which comprises a samarium-iron-nitrogen based alloy, where crystal grains included therein are larger than 0.04 μm and 5 μm or less in average grain diameter, and an oxygen content (wt%) and the average grain diameter (μm) of the crystal grains satisfy the relation given by the following formula (1): (Oxygen content)×(Average grain diameter of crystal grains)<2.2 (1).

SELECTED DRAWING: Figure 1

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【課題】単磁区粒径近傍まで粉砕された結晶粒子を含有し、かつ保磁力に優れた、サマリウム−鉄−窒素系焼結磁石を提供する。
【解決手段】サマリウム−鉄−窒素系合金を含有し、
含有する結晶粒子の平均粒径が０．０４μｍより大きく５μｍ以下であり、
酸素含有率が０．７重量%以下であるサマリウム−鉄−窒素系焼結磁石を提供する。
また、サマリウム−鉄−窒素系合金を含有し、
含有する結晶粒子の平均粒径が０．０４μｍより大きく５μｍ以下であり、
酸素含有率（重量％）と、前記結晶粒子の平均粒径（μｍ）とが、以下の式（１）の関係を満たすサマリウム−鉄−窒素系焼結磁石を提供する。
（酸素含有率）×（結晶粒子の平均粒径）＜２．２ ・・・（１）
【選択図】図１