TY - JOUR
T1 - Relaxor behavior and electrothermal properties of Sn- and Nb-modified (Ba,Ca)TiO3 Pb-free ferroelectric
AU - Venkateshwarlu, Sarangi
AU - Nayak, Sanjib
AU - Marlton, Frederick P.
AU - Weyland, Florian
AU - Novak, Nikola
AU - Maurya, Deepam
AU - Veerabhadraiah, Yashaswini
AU - Borkiewicz, Olaf
AU - Beyer, Kevin A.
AU - Jorgensen, Mads R.V.
AU - Pramanick, Abhijit
PY - 2020/4
Y1 - 2020/4
N2 - Relaxor ferroelectrics have drawn attention for possible applications in solid-state cooling and thermal energy harvesting, owing to their electrothermal energy conversion properties. Here, we have synthesized and characterized the structure-property correlations of a new Sn- and Nb-doped (Ba,Ca)TiO3 relaxor ferroelectric with large pyroelectric and electrocaloric effects over a broad temperature range. We observed two peaks for the temperature-dependent pyroelectric coefficient: (i) -(∂P/∂T) ∼ 563 μC/(m2 K) at T∼ 270 K and (ii) -(∂P/∂T) ∼ 1021 μC/(m2 K) at T∼ 320 K. In addition, a broad peak for electrocaloric temperature change is observed near 320 K with a relative cooling power of ∼17 J/kg. These properties could be correlated to structural changes observed using X-ray diffraction at two different temperature ranges in the material. Analysis of high-energy X-ray scattering and specific heat capacity data revealed a transition from the cubic to tetragonal phase near Tm∼ 320 K, whereas an additional increase in the tetragonality (c/a) of the polar phase is observed below Ts∼ 270 K.
AB - Relaxor ferroelectrics have drawn attention for possible applications in solid-state cooling and thermal energy harvesting, owing to their electrothermal energy conversion properties. Here, we have synthesized and characterized the structure-property correlations of a new Sn- and Nb-doped (Ba,Ca)TiO3 relaxor ferroelectric with large pyroelectric and electrocaloric effects over a broad temperature range. We observed two peaks for the temperature-dependent pyroelectric coefficient: (i) -(∂P/∂T) ∼ 563 μC/(m2 K) at T∼ 270 K and (ii) -(∂P/∂T) ∼ 1021 μC/(m2 K) at T∼ 320 K. In addition, a broad peak for electrocaloric temperature change is observed near 320 K with a relative cooling power of ∼17 J/kg. These properties could be correlated to structural changes observed using X-ray diffraction at two different temperature ranges in the material. Analysis of high-energy X-ray scattering and specific heat capacity data revealed a transition from the cubic to tetragonal phase near Tm∼ 320 K, whereas an additional increase in the tetragonality (c/a) of the polar phase is observed below Ts∼ 270 K.
KW - electrical properties
KW - ferroelectric
KW - X-ray diffraction
UR - http://www.scopus.com/inward/record.url?scp=85079488423&partnerID=8YFLogxK
U2 - 10.1557/jmr.2020.25
DO - 10.1557/jmr.2020.25
M3 - Review
AN - SCOPUS:85079488423
SN - 0884-2914
VL - 35
SP - 1017
EP - 1027
JO - Journal of Materials Research
JF - Journal of Materials Research
IS - 8
ER -