Ion-beam sputtering deposition and magnetoelectric properties of layered heterostructures (FM/PZT/FM)_n, where FM – Co or Ni₇₈Fe₂₂

¹ Scientific-Practical Materials Research Centre NAS of Belarus, 19 P. Brovki Street, Minsk 220072, Belarus
² Institute of Physics, Polish Academy of Science, 02-668 Warsaw, Poland
³ A.A. Galkin Donetsk Physico-Technical Institute, NNU, 83114 Donetsk, Ukraine
⁴ International Laboratory of High Magnetic Fields and Low Temperatures, 53-421 Wroclaw, Poland

^a e-mail: sazan@ifpan.edu.pl

Received: 10 December 2012
Revised: 17 May 2013
Accepted: 25 June 2013
Published online: 7 August 2013

Abstract

Magnetoelectric properties of layered heterostructures (FM/PZT/FM)_n (n≤ 3) obtained by ion-beam sputtering deposition of ferromagnetic metal (FM), where FM is the cobalt (Co) or permalloy Ni₇₈Fe₂₂, onto ferroelectric ceramic based on lead zirconate titanate (PZT) have been studied. The polished ferroelectric plates in thickness from 400 to 20 μm were subjected to finished treatment by ion-beam sputtering. After plasma activation they were covered by the ferromagnetic films from 1 to 6 μm in thickness. Enhanced characteristics of these structures were reached by means of both the thickness optimization of ferroelectric and ferromagnetic layers and obtaining of ferromagnetic/ferroelectric interfaces being free from defects and foreign impurities. Assuming on the basis of analysis of elastic stresses in the ferromagnetic film that the magnetoelectric effect forms within ferromagnetic/ferroelectric interface, the structures with 2–3 ferromagnetic layers were obtained. In layered heterostructure (Py/PZT/Py)₃, the optimal thickness of ferromagnetic film was 2 μm, and outer and inner ferroelectric layers had 20 μm and 80 μm in thickness, respectively. For such structure the maximal magnetoelectric voltage coefficient of 250 mV/(cm Oe) was reached at a frequency 100 Hz in magnetic field of 0.25 T at room temperature. The structures studied can serve as energy-independent elements detecting the change of magnetic or electric fields in electronic devices based on magnetoelectric effect.