Small dc magnetic field response of magnetoelectric laminate composites

We have found that small long-type magnetoelectric (ME) laminate composites of magnetostrictive Tb1−xDyxFe2−y and piezoelectric Pb(Zr,Ti)O3 are quite sensitive to small dc magnetic field (Hdc) variations, when driven by a constant ac magnetic field. The sensitivity limit is Hdc<10−3Oe (10−7Tesla) using a constant amplitude low frequencies drive, and Hdc<10−4Oe (10−8Tesla) under resonant drive. In addition, an unusual ME switching effect—a 180° phase shift—was observed, in response to changes in the sign of a small Hdc.