Inverse Magnetocaloric Effect and the Magnetostructural Transition in Pr0.15Ca0.85MnO3 Manganite

Magnetic and magnetocaloric properties of electron-doped Pr
_0.15
Ca
_0.85
MnO
₃
(orthorhombic space group
Pnma,
no. 62,
oP
20) manganite have been studied. Low field magnetization measurements suggest that the sample orders antiferromagnetically at 147 K (
$T_{N}$
). Magnetocaloric effect (MCE) has been estimated in terms of isothermal magnetic entropy change (
$\Delta S_{m}$
) and the maximum
$\Delta S_{m}$
value is about 6.4 Jkg
⁻¹
K
⁻¹
at 137.5 K for 70 kOe field change. Low-temperature powder X-ray diffraction studies reveal a change from orthorhombic (space group
Pnma
, no. 62,
oP
20) crystal structure to monoclinic (space group
$P 2_{1}/m$
, no. 11–2,
mP
20) structure below 140 K. The inverse MCE shows a maximum value around the magnetostructural transition temperature. Electrical resistivity and electron paramagnetic resonance (EPR) spectroscopy results reveal hopping conduction in the paramagnetic state.