A rotor assembly for an electric machine, e.g., of an electrified powertrain, includes a rotor having inner and outer diameter surfaces, and a rotor shaft connected to and surrounded by the rotor. The rotor has equally-spaced rotor magnetic poles each having a quadrature-axis (“q-axis”) and a pair of direct-axes (“d-axes”). At each of magnetic pole of the rotor, the rotor defines at least three arcuate notches, including a center notch bisected by the q-axis and a pair of additional arcuate notches symmetrically flanking the center notch. The rotor may include embedded permanent magnets, which may be arranged in a dual V-shaped configuration. Each additional notch may be positioned within a sweep of a top-layer opening angle of the magnets. The center notch and/or the pair of additional notches may define tangentially-continuous fillets which smoothly transition the notch into the outer diameter surface.