In spite of both technical and fundamental importance, reversal of a macroscopic magnetization by an electric field (E) has been limitedly realized and remains as one of great challenges. Here, we report the realization of modulation and reversal of
large magnetization (M) by E in a multiferroic crystal Ba0.5Sr1.5Zn2(Fe0.92Al0.08)12O22, in which a transverse conical spin state exhibits a remanent M and electric polarization below ~150 K. Upon sweeping E between +- 2 MV/m, M is quasi-linearly varied between +- 2 {mu}B/f.u., resulting in the M reversal. Moreover, the remanent M shows non-volatile changes of {Delta}M = +- 0.15 {mu}B/f.u., depending on the history of the applied electric fields. The large modulation and the non-volatile two-states of M at zero magnetic field are observable up to ~150 K where the transverse conical spin state is stabilized. Nuclear magnetic resonance measurements provide microscopic evidences that the electric field and the magnetic field play an equivalent role, rendering the volume of magnetic domains change accompanied by the domain wall motion. The present findings point to a new pathway for realizing the large magnetization reversal by electric fields at fairly high temperatures.
In contrast to the Pb-based magnetoelectric laminates (MELs), we find in the BaTiO3 and NiFe2O4 laminates (number of layers n = 5-25) that the longitudinal magnetoelectric (ME) voltage coefficient Alpha E33 becomes much larger than the transverse one
due to preferential alignment of magnetic moments along the NiFe2O4 plane. Moreover, upon decreasing each layer thickness down to 15 um, we realize enhanced Alpha E33 up to 18 mV/ (cm Oe) and systematic increase of the ME sensitivity in proportion to n to achieve the largest in the Pb-free MELs (400*10^-6V/Oe), thereby providing pathways for tailoring ME coupling in mass-produced, environment friendly laminates.
