Spontaneous and field-induced magnetostructural phase transitions in electron-doped manganites (Sm,Nd)0.2Ca0.8MnO3

Study of calcium doping effect on thermophysical properties of some perovskite manganites

“…1-4 in the range 2 K ≤ T ≤ 300 K. It is noticed from the Fig. 1 that the computed specific heat curve for Nd 0.04 Sm 0.16 Ca 0.8 MnO 3 is in agreement with the experimental data [4] and the trends of variations exhibited by the experimental and theoretical results are almost similar except for the strong peak shown by the measured data at ∼150 K. This observed peak owes its origin to the occurrence of the charge and orbital ordering effects in the manganites. However, this peak could not be reproduced from our theoretical results due to the exclusion of the charge and ordering effects in MRIM.…”

“…The electronic, transport, ferromagnetic and CMR properties depend on the concentration of Mn +4 ions, which are created by the substitution of trivalent R ions with divalent A ions. These manganese oxides exhibit the semiconducting behavior in the paramagnetic phase and the metallic behavior in the ferromagnetic state near Tc [3,4].…”

“…Particularly in Nd 0.04 Sm 0.16 Ca 0.8 MnO 3 , the transition from paramagnetic to antiferromagnetic state is accompanied by a structural transformation from an orthorhombic pnma phase to a monoclinic P2 1 /m phase [4].…”

“…The variation of specific heat of Nd0.04Sm0.16Ca0.8MnO3 with temperature, where solid line (-) and the squares ( ) are the present theoretical and the experimental[4] results, respectively.…”

Enhancement of the phase separation aspect in the electron doped manganite Ca0.8Sm0.16Nd0.04MnO3

“…These features are due to the structural transformation from the high temperature orthorhombic Pnma phase, which is paramagnetic, into the low temperature monoclinic P2 1 /m phase, which is an anti-ferromagnet of C type. Strong magnetic field causes a collapse of the low temperature phase in Ca 0.85 Sm 0.15 MnO 3 , resulting in a field induced first order transition from the monoclinic anti-ferromagnetic phase to the orthorhombic ferromagnetic phase [16][17][18][19]. The P2 1 /m phase at low temperatures shows the signatures of phase separation, the ferromagnetic clusters and anti-ferromagnetic clusters of G type being present in an anti-ferromagnetic matrix of C type [18].…”