A electrically-insulating paramagnetic material will become spin polarized in
the presence of an electric field if there exists an electron EDM. A sample
polarized in that way develops a net magnetization that might be detectable
using state-of-the-art SQUID magnetometers. This electric-field-induced spin
order increases as the sample temperature decreases. We have identified a
candidate material, gadolinium gallium garnet, that has a low conductivity and a
high concentration of heavy ions, Gd3+. The net electric dipole moment of
unpaired electrons in the valence shell of Gd3+ is predicted to be high. With a
practical sample size of 100 cubic centimeters and a typical applied electric
field of 10 kilovolts per centimeter, we expect, after 10 days of data
averaging, to place an experimental limit on the electron EDM of approximately
1e-29 e-cm, which is about 100 times better than the current limit set by the
thallium beam experiment at Berkeley.
SQUID sensor studies
X-ray diffraction
EPR measurement (point defects)
Magnetic susceptibility measurements
Spin dilution -- solid state reaction
Other groups
- Hunter at Amherst
- Lamoreaux at Yale
- Budker at Berkeley
- Reno