Abstract: EDM measurements on diamagnetic atoms probe CP-violating effects in the nucleus. Some types of these Beyond-Standard-Model effects are known to be strongly enhanced in 225Ra due to octupole deformation of the nucleus. Other favorable characteristics of 225Ra include a high atomic number (Z = 88), a ground state of 1S0, and a nuclear spin 1/2. An EDM search is carried out on this radioactive isotope (half-life 15 d) using laser-cooled atoms. Meanwhile, the stable isotope 171Yb shares several characteristics, including 1S0 and nuclear spin 1/2, and is particularly useful as a proxy of 225Ra for developing laser trapping and probing techniques, for testing various measurement schemes, and for investigating systematic errors. Furthermore, 171Yb atoms can be placed within 0.1 mm of 225Ra, and act as a co-magnetometer. A laser trap of Yb atoms for an EDM measurement is under development.