  We have carried out a comprehensive study of the temperature structure of
plasmoids, which successively occurred in recurrent active region jets. The
multithermal plasmoids were seen to be travelling along the multi-threaded
spire as well as at the footpoint region in the EUV/UV images recorded by the
Atmospheric Imaging Assembly (AIA). The Differential Emission Measure (DEM)
analysis was performed using EUV AIA images, and the high-temperature part of
the DEM was constrained by combining X-ray images from the X-ray telescope
(XRT/Hinode). We observed a systematic rise and fall in brightness, electron
number densities and the peak temperatures of the spire plasmoid during its
propagation along the jet. The plasmoids at the footpoint (FPs) (1.0-2.5 MK)
and plasmoids at the spire (SPs) (1.0-2.24 MK) were found to have similar peak
temperatures, whereas the FPs have higher DEM weighted temperatures (2.2-5.7
MK) than the SPs (1.3-3.0 MK). A lower limit to the electron number densities
of plasmoids - SPs (FPs) were obtained that ranged between
3.4-6.1$\times$10$^{8}$ (3.3-5.9$\times$10$^{8}$) cm$^{-3}$ whereas for the
spire, it ranged from 2.6-3.2$\times$10$^{8}$ cm$^{-3}$. Our analysis shows
that the emission of these plasmoids starts close to the base of the jet(s),
where we believe that a strong current interface is formed. This suggests that
the blobs are plasmoids induced by a tearing-mode instability.
