Direct and converse magneto-electric coupling in ferromagnetic shape memory alloys based thin film multiferroic heterostructures

The ferromagnetic shape memory driven alterations in strain mediated direct and converse magnetoelectric coupling (DME & CME) was realized in sputtered deposited PZT/Ni-Mn-In multiferroic hetero-junctions. The ferroelectric (P-E loops), dielectric (e vs frequency, epsilon-E), and voltage modulated magnetic anisotropy measurements (M-E curves) were executed in the plane (hard axis) and out of the plane (easy axis) of the functional magnetic material based PZT/Ni-Mn-In bilayer structure. A gain of similar to 16 mu C/cm(2) in maximum polarization (P-max) and similar to 12% in tunability (n(r)) were observed along an easy magnetic axis of Ni-Mn-In. The butterfly shaped normalized magnetization (M/M-s) vs electric field (applied across the heterostructure) [M-E] plots evident the strain character of CME coupling. The co-action of (i) dissimilar carrier concentration between high symmetric austenitic cubic phase and low symmetry martensite phase of ferromagnetic shape memory alloys and (ii) martensitic transformation induced magnetization change in Ni-Mn-In cause an electrical field modulated hall resistivity; a change of similar to 42% in hall resistivity was observed at 60 kV/cm electric field and 0.2T magnetic field at 270 K. The reversible manipulation of remnant magnetization (M-r) with applied electric field was demonstrated as on/off switch using a square pulse of 60 kV/cm amplitude. (C) 2015 AIP Publishing LLC.