Analytical and Experimental Studies on Layered Multiferroic Materials (Macro-Nano)
October 21, 2011
Greg P. Carman
MAE Dept UCLA
This presentation reviews the research studies conducted in the Active Materials Lab at UCLAon multiferroic heterostructures. Layered multiferroic materials in this presentation are defined
as composites that couple electric and magnetic fields through a strain mediated mechanism. Recently this area has received considerable attention due to the unique coupling present
between electric and magnetic fields for use in sensitive magnetometers or in memory devices. Experimental work demonstrates that in the macro-scale the magnetoelectric coupling
parameters can be increased using magnetic field, electric field, and mechanical load bias to optimize the magnetic domain structure. Disagreement between analytical and experimental
measurements is explained using a multi-physics shear lag and demagnetization model. An analytical model combining electro-magneto-mechanical wave phenomenon is used to describe
plane wave propagation in continuous media. Distinct differences are analytically found in wave propagation in multiferroic materials as contrasted with conventional materials.
Fabrication and experimental work on thin film and nanoscale multiferroics is presented. Experimental results show that electric field induced magnetic easy axis changes is achievable
in both films and single domain elements. Using electric field induced polarization variant motion in a single crystal ferroelectric material, remnant strains are used to control a metastable
magnetic single domain structure.