  Mutual control of the electricity and magnetism in terms of magnetic (H) and
electric (E) fields, the magnetoelectric (ME) effect, offers versatile low
power-consumption alternatives to current data storage, logic gate, and
spintronic devices. Despite its importance, E-field control over magnetization
(M) with significant magnitude was observed only at low temperatures. Here we
have successfully stabilized a simultaneously ferrimagnetic and ferroelectric
phase in a Y-type hexaferrite single crystal up to T=450K and demonstrated the
reversal of large non-volatile M by E field close to room temperature.
Manipulation of the magnetic domains by E field is directly visualized at room
temperature by using magnetic force microscopy. The present achievement
provides an important step towards the application of bulk ME multiferroics.
