  The DC transport properties of and the radio-frequency (RF) wave absorption
(at 2.525 MHz) in a sample of La$_{0.67}$Sr$_{0.33}$MnO$_{3}$ prepared by
floating-zone method are measured. The Curie temperature, $T_{c}$, of the
sample is about 374 K. Giant temperature and magnetic-field variations in RF
absorption are found in the vicinity of $T_{c}$. Relative change of the RF
absorption in magnetic field (magnetoabsorption) is about 67% in field 2.1 kOe
and about 55% in field 1 kOe. This giant magnetoabsorption effect can be used
to develop RF devices controlled by temperature and low magnetic field. A weak
temperature dependence of magnetoabsorption for the sample studied in the range
from room temperature to about 350 K makes it especially attractive for
practical use. The RF study supplemented with transport, magnetoresistive and
magnetic measurements enables us to discuss the optimal properties of manganite
samples for observation of giant magnetoabsorption in low field.
