Pyroelectric effects in magnetoelectric multilayer composites

Magnetoelectric and pyroelectric properties have been investigated in heterostructures of nickel zinc ferrite (NZFO)–lead zirconate titanate (PZT) and lanthanum calcium manganite (LCMO)–PZT. The magnetoelectric (ME) coupling, mediated by mechanical strain, is found to be two orders of magnitude stronger in NZFO–PZT than in LCMO–PZT. The pyroelectric effect is investigated by measuring the current through the sample as the temperature is varied at 0.1 K/s. For NZFO–PZT the pyroelectric coefficient is in the range 0.2–15 nC/cm2 K, depending on the temperature. A much weaker current is observed in LCMO–PZT. A reversal in the current direction is detected when the thermal cycle is switched from heating to cooling. The pyroelectric coefficient is found to scale with the strength of ME interactions. A clear correlation between pyroelectric current and ME interactions is evident from the results.