Search for anomalous spin-spin interactions between electrons using a DC SQUID

Abstract

We use a paramagnetic salt TbF 3 with a DC SQUID to search for possible anomalous spin-spin interaction of two rotating Dy 6Fe 23 polarized bodies and two rotating HoFe 3 polarized bodies with the TbF 3 paramagnetic salt. We set limits on the electron-electron spin interaction. In terms of a standard dipole-dipole form, the limits are (1.2±2.0)×10 -14 for the anomalous spin-spin interaction of electrons in terms of the interaction strength between the magnetic moments of the electrons. Compared to previous results, this is a forty-fold improvement.