PYROELECTRIC AND DIELECTRIC-PROPERTIES OF SOME LIGHT RARE-EARTH ORTHOCHROMITES

The measurement of pyroelectic coefficient (p) and dielectric constant (K) of rare-earth orthochromites RCrO3, where R=praseodymium, neodymium, samarium, europium and gadolinium, have been reported in the temperature range 300 to 450 K. Pyroelectric data show that praseodymium and neodymium orthochromites do not have ferroelectric phase in this temperature range, whereas samarium, europium and gadolinium orthochromites are ferroelectric. The dielectric data support the above conclusion. Spontaneous polarization (Ps) for samarium, europium and gadolinium have also been evaluated. The maximum values for Ps are 4.6 × 10-3 C m-2 for SmCrO3, 0.42 C m-2 for EuCrO3 and 0.72 C m-2 for GdCrO3. © 1990 Chapman and Hall Ltd.