Giant anelastic responses in (BaZrO₃-ZnO)-BaTiO₃ composite materials

¹ Department of Engineering Physics, University of Wisconsin - Madison, WI 53706-1687, USA
² Materials Science Program, University of Wisconsin - Madison, WI 53706-1687, US A
³ Department of Engineering Physics, Engineering Mechanics Program, Materials Science Program, University of Wisconsin - Madison, WI 53706-1687, USA

^a lakes@engr.wisc.edu

Received: 30 January 2011
Accepted: 27 February 2011

Abstract

Composite materials containing particulate BaTiO₃ inclusion have been fabricated with BaZrO₃-ZnO as the matrix. Giant anelastic responses (abrupt increase in modulus and damping vs. temperature) have been observed after 75 ^°C aging 24 h in these composites in the temperature region far below the Curie point of BaTiO₃. Anomalies disappeared after 185 ^°C aging 4 h. Such responses are attributed to the constraining negative-stiffness effect of the inclusion. An oxygen vacancy mechanism has been discussed which is considered to be responsible for the negative-stiffness effect. The present work is novel in terms of the idea of manipulation of negative stiffness in ferroelastic inclusions to achieve the desired composite properties.