Anomalous Nernst Effect in Perovskite La0.5Ca0.5CoO3

We report the occurrence of the anomalous Nernst effect (ANE) in polycrystalline perovskite La
_0.5
Ca
_0.5
CoO
₃
. The sample is ferromagnetic (FM) below
$T_{C}$
= 147 K and resistivity shows non-metallic behavior above and below
$T_{C}$
with only a small negative magnetoresistance (MR) (~2%) around
$T_{C}$
. The field dependence of magnetization at 10 K shows large hysteresis with a coercive field of 6 kOe but a small magnetization ~
$0.64 ~\mu _{B}$
/Co even in a field of 50 kOe, which indicates the presence of magnetically heterogeneous ground state consisting of FM and non-FM phases. The field dependence of the Nernst thermopower (
$S_{xy}$
) at low temperatures shows complete saturation, but the magnetization does not. This indicates that the ANE in La
_0.5
Ca
_0.5
CoO
₃
depends only on the transport properties of the FM phase, while it is not affected by the non-FM phase. Due to the higher value of remnant
$S_{xy}$
, the magnetized polycrystalline sample exhibits ANE in the absence of an external magnetic field.