Resonance magnetoelectric effect without a bias field in a piezoelectric langatate-hysteretic ferromagnet monolithic structure
The frequency, field, temperature, and amplitude characteristics of the direct magnetoelectric effect are studied in a planar monolithic structure consisting of a piezoelectric langatate crystal and a layer of electrolytic nickel. A relation between the magnetic and magnetoelectric properties of the structure is demonstrated, which explains the effects observed in structures with hysteretic layers. At the planar acoustic resonance frequency of the structure (about 70 kHz), the effect amounting to 23 V/(Oe cm) in the absence of a bias field is discovered. In the temperature interval 150-400 K, the amount of the effect changes nearly twofold, the resonance frequency changes by about 1%, and the Q factor on cooling rises to about 8 × 103. The field sensitivity of the structure is on the order of 1 V/Oe, which makes it possible to detect magnetic fields with an amplitude down to ∼10-6 Oe.