Clamped Ferroelectric and Magnetic Domain Walls and their Application to Memory Engineering

A family of rare-earth metal manganites are antiferromagnetic (AFM) ferroelectrics and some of these may show also weak ferromagnetism. First we will show how to observe the ferroelectric (FEL) and AFM domain structures by the interference effects of second harmonic generation (SHG). Second, the observed clamping of the AFM domain wall (DW) to the FEL domain boundary (DB) is intuitively explained by the group theoretical consideration of the magnetic anisotropy energy depending upon the sign of the FEL polarization. Third, the application of these clamped DW-DB to the memory engineering will be briefly discussed.