Magnetic, thermal and transport properties of phase-separated La0.27Nd0.4Ca0.33MnO3
Journal of Physics: Condensed Matter
The magnetic, resistive and thermal properties of the phase-separated compound La 0.27 Nd 0.4 Ca 0.33 MnO 3 have been experimentally studied. The sample is found to experience a charge/orbital ordering transition at ∼175 K and an antiferromagnetic (AFM) transition at ∼156 K without a magnetic field. A magnetic field stabilizes the ferromagnetic (FM) order and the field-induced FM phase coexists with the AFM phase under a field below 2 T in the temperature range below T C ≈ 110 K. However, the
... 0 K. However, the magnetic entropy change accompanying the AFM-FM transition is negligibly small when T C < T N , grows rapidly as T C approaches T N under the driving of an applied field, and saturates at a value of ∼4 J kg −1 K −1 when T C > T N . A general relation between resistivity and magnetization, ρ = A 0 T exp[(ε − 800m 2 )/T ] (m = normalized magnetization), is established for the paramagnetic phase, which is also applicable to other compounds with different characters, such as the La 0.67 Ca 0.33 MnO 3 film and the La 0.474 Bi 0.193 Ca 0.33 Mn 0.994 Cr 0.006 O 3 and Eu 0.55 Sr 0.45 MnO 3 ceramics. In the FM state, the resistivity is quite sensitive to the change of spin alignment and exhibits an exponential decrease with magnetization ρ = ρ 0 exp(−22.7m). Field-induced phase separation is believed to be responsible for the distinct properties of La 0.