A method of fabricating a ferrite for use in a resistivity logging tool includes mixing a ferrite powder with a binder to provide a mixture, and pressing the mixture into a mold to form the ferrite. The mold exhibits a specific geometry corresponding to a channel defined on an inner surface of a bobbin associated with the resistivity logging tool, and the channel is arcuate and extends at an angle offset from a central axis of the bobbin. At least one of a length, a width, and a thickness of the ferrite is then adjusted to manipulate a magnetic permeability of the ferrite in a direction of a magnetic field passing through the ferrite.