Embodiments of the present invention include systems and methods for low-rate electrochemical (wet) etch that use a net cathodic current or potential. In particular, some embodiments achieve controlled etch rates of less than 0.1 nm/s by applying a small net cathodic current to a substrate as the substrate is submerged in an aqueous electrolyte. Depending on the embodiment, the aqueous electrolyte utilized may comprise the same type of cations as the material being etched from the substrate. Some embodiments are useful in etching thin film metals and alloys and fabrication of magnetic head transducer wafers.