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

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 Ni 78 Fe 22 , onto ferroelectric ceramic based on lead zirconate titanate (PZT) have been studied. The polished ferroelectric plates in thickness from 400 to 20 μ m were subjected to finished treatment by ion-beam sputtering. After plasma activation they were covered by the ferromagnetic films from 1 to 6 μ m 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 μ m, and outer and inner ferroelectric layers had 20 μ m and 80 μ m 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.