An electric machine comprising a permanent magnet rotor assembly is provided. The electric machine comprises a permanent magnet rotor assembly comprising a plurality of permanent magnets coupled to a rotor disk and a plurality of magnet shims coupled to the plurality of permanent magnets opposite the rotor disk. Each magnet shim of the plurality of magnet shims has a substantially complementary shape as a respective permanent magnet of the plurality of permanent magnets. The electric machine further comprises a stator core comprising a plurality of stator teeth that define a plurality of slots therebetween. At least one of the plurality of magnet shims is configured to direct magnetic flux from at least one of the plurality of permanent magnets to at least one stator tooth of the plurality of stator teeth.