R-t-b-based sintered magnet

An R-T-B-based sintered magnet comprising:

• a rare earth element R, a transition metal element T, B, Cu, and Ga,
• wherein the R-T-B-based sintered magnet contains at least one of Nd and Pr as R,
• the R-T-B-based sintered magnet contains at least Fe of Fe and Co as T,
• the R-T-B-based sintered magnet includes
• a plurality of main phase grains including a crystal of R2T14B, and
• a plurality of grain boundary multiple junctions which are grain boundary phases surrounded by at least three of the main phase grains,
• the plurality of grain boundary multiple junctions are classified into at least two phases of a transition metal rich phase and an R-rich phase,
• the R-rich phase is classified into at least two phases of a Cu-poor phase and a Cu-rich phase,
• the transition metal rich phase contains R, T, and Ga, and is a phase satisfying the following Formula T1,
• the R-rich phase is a phase satisfying the following Formulas R1 and R2,
• the Cu-poor phase is a phase satisfying the following Formula C1,
• the Cu-rich phase is a phase satisfying the following Formula C2,
• the transition metal rich phase, the Cu-poor phase, and the Cu-rich phase satisfy the following Formula 1, and
• the Cu-poor phase and the Cu-rich phase satisfy the following Formula 2.
• 1.50≤([Fe]+[Co])/[R]≤3.00 (T1)
• 0.00≤([Fe]+[Co])/[R]<1.50 (R1)
• 0.00≤[O]/[R]<0.35 (R2)
• 0.00≤[Cu]/[R]<0.25 (C1)
• 0.25≤[Cu]/[R]≤1.00 (C2)
• [[Fe] in the above Formula T1 and the Formula R1 is a concentration of Fe at the grain boundary multiple junction, [Co] in the above Formula T1 and the above Formula R1 is a concentration of Co at the grain boundary multiple junction, [R] in the above Formula T1, the above Formula R1, the above Formula R2, the above Formula C1, and the above Formula C2 is a concentration of R at the grain boundary multiple junction, [O] in the above Formula R2 is a concentration of O at the grain boundary multiple junction, [Cu] in the above Formula C1 and the above Formula C2 is a concentration of Cu at the grain boundary multiple junction, and units of [Fe], [Co], [R], [O], and [Cu] are each atom %.]
• 0.30≤N1/(N1+N2+N3)≤0.60 (1)
• 0.03≤N3/N2≤0.20 (2)
• [N1 in the above Formula 1 is the number of transition metal rich phases of the plurality of grain boundary multiple junctions on a cross section of the R-T-B-based sintered magnet, and N2 in the above Formulas 1 and 2 is the number of Cu-poor phases of the plurality of grain boundary multiple junctions on the cross section of the R-T-B-based sintered magnet, and N3 in the above Formulas 1 and 2 is the number of Cu-rich phases of the plurality of grain boundary multiple junctions on the cross section of the R-T-B-based sintered magnet.]