Ferroelectric Domain Imaging Multiferroic Films Using Piezoresponse Force Microscopy

Recently, multiferroic materials with the magnetoelectric coupling of ferroelectric (or anti‐ ferroelectric) properties and ferromagnetic (or antiferromagnetic) properties have attracted a lot of attention.[1-4] Among them, BiFeO3(BFO) and YMnO3has been intensively studied. For such ABO3perovskite structured ferroelectric materials, they usually show antiferromag‐ netic order because the same B site magnetic element except BiMnO3 is ferromagnet. While for the A2BBO6 double perovskite oxides, the combination between B and B’ give rise to a ferromagnetic coupling. They are also expected to be multiferroic materials. Several bis‐ muth-based double perovskite oxides (BiBBO6) have aroused great interest like Bi2NiMnO6, La2NiMnO6, BiFeO3-BiCrO3. But as we know, few researches are focused on Bi2FeMnO6. We believe it is particular interesting to investigate Bi2FeMnO6 (BFM). The origin of the ferro‐ magnetism in these compounds has been discussed in many reports. According to Goode‐ nough-Kanamori’s (GK)rules, many ferromagnets have been designed through the coupling of two B site ions with and without eg electrons.In BFM, the 180 degree -Fe3+-O-Mn3+bonds is quasistatic, partly because the strong Jahn-Teller uniaxial strain in an octahedral site.Be‐ cause the complication of the double perovskite system, there are still some questions about the violation of GK rules in some cases and the origin of the ferromagnetism or antiferro‐ magnetism.The other problem is the bad ferroelectric properties. In order to characterization of their ferroelectric/piezoelectric properties, scanning probe microscopy (SPM) techniques were used.