Sintered rare earth magnet, method of producing the same, and rotating machine

A sintered rare earth magnet, comprising:

• a main phase composed of R2T14B, where:
• R comprises as a main component one or more rare earth element selected from:
• Nd,
• Pr, and
• Nd and Pr, and
• T represents one or more transition metal element selected from:
• Fe, and
• Fe and Co;
• and
• a grain boundary phase containing a higher proportion of R than the main phase;
• wherein:
• the main phase includes one or more heavy rare earth element selected from:
• Dy,
• Tb, and
• Dy and Tb;
• at least a part of main phase grains of the main phase includes at least three regions where the concentration of the heavy rare earth elements differs, the three regions being:
• a low concentration region where the concentration of the heavy rare earth elements is the lowest in three regions,
• a high concentration region where the concentration of the heavy rare earth elements is the highest in three regions, and
• an intermediate concentration region where the concentration of the heavy rare earth elements is higher than the low concentration region and is lower than the high concentration region,
• the three regions exist in order of the low concentration region, the high concentration region, and the intermediate concentration region, from the low concentration region in the main phase grain toward the grain boundary phase;
• an average area ratio of the high concentration region with respect to the main phase is 5% or more;
• main phase grains wherein the high concentration region contacts an overall periphery of the low concentration region and the intermediate concentration region contacts an overall periphery of the high concentration region exist at 5% or more in the sintered rare earth magnet,
• an average concentration value of the heavy rare earth element in the intermediate concentration region is determined as the average concentration value of the heavy rare earth element from the maximum concentration of the heavy rare earth element to the grain boundary phase, and
• a value of the following formula (A) is in a range of 0.2 to 0.8:
• (γ−α)/(β−α) (A)
• where:
• α=the minimum concentration of the heavy rare earth element in the main phase,
• β=the maximum concentration of the heavy rare earth element in the main phase, and
• γ=the average concentration value of the heavy rare earth element in the intermediate concentration region.