Magnetic and Magnetocaloric Properties of Multiferroic Oxides Gd0.5Y0.5MnO3 and Eu0.5Dy0.5MnO3

In this article, crystal structure, magnetism, heat capacity, magnetocaloric effect (MCE), and electrical resistivity of mixed rare-earth Gd
_0.5
Y
_0.5
MnO
₃
and Eu
_0.5
Dy
_0.5
MnO
₃
manganites have been studied. Temperature-dependent magnetization M(T) measurements suggest an antiferromagnetic order just below 6 K in Gd
_0.5
Y
_0.5
MnO
₃
, while no magnetic transition has been observed down to 5 K in Eu
_0.5
Dy
_0.5
MnO
₃
. Heat capacity data reveal anomalies at 40 and 42 K in Gd
_0.5
Y
_0.5
MnO
₃
and Eu
_0.5
Dy
_0.5
MnO
₃
, and these may correspond to Mn magnetic order as previously reported. The magnetization values are 2.8 and 3 μ
_B
/f.u. in 70 kOe field at 5 K for Gd
_0.5
Y
_0.5
MnO
₃
and Eu
_0.5
Dy
_0.5
MnO
₃
, respectively. MCE has been estimated in terms of isothermal magnetic entropy change (ΔS
_m
) at low temperatures. The maximum values of ΔS
_m
are about -11 and -6.2 J kg
^-1
, respectively, for Gd
_0.5
Y
_0.5
MnO
₃
and Eu
_0.5
Dy
_0.5
MnO
₃
samples for a field change of 70 kOe at 8 K. Electrical resistivity of Gd
_0.5
Y
_0.5
MnO
₃
and Eu
_0.5
Dy
_0.5
MnO
₃
shows variable range polaron hopping behavior in the temperature range of 210-350 K.