X-ray diffraction patterns of the samples annealed at various temperatures.
SEM micrograph of samples annealed at various temperatures of (a) 600 °C, (b) 700 °C, (c) 800 °C, and (d) 1000 °C.
Temperature dependence of magnetization recorded in the ZFC (open symbols) and FC (solid symbols) modes under an applied magnetic field H = 0.01 T. Inset shows the first derivative of M-T curve in FC model for the 17 nm sample.
Temperature dependence of ZFC magnetization of the 17 nm sample in different applied magnetic fields.
H dependence of Tp (solid line to guide the eye). Inset: (a) Tp vs H for H ≤ 0.1 T; Dashed curve is the fitting SPM curve extrapolated to the field higher than 0.05 T. (b) Tp vs H for 0.2 T ≤ H ≤ 4.5 T. (c)-(d) Fitting AT line to the experimentally obtained data (circle points). A good agreement was achieved by using parameters: = 2 for H ≤ 0.05 T = 2/3 for 0.06 T ≤ H ≤ 0.1 T, and = 2/3 for 0.2 T ≤ H ≤ 4.5 T.
(a)-(c) Initial magnetization isotherms M (H) for the 17, 28, and 43nm samples at different temperatures around magnetic transition temperature (TC ). The red curve is the data measured at TC ; (d) Magnetization as a function of applied field at T = 220 K (solid squares) associated to the Langevin behavior (red curve) of 17 nm sample.
(a)-(c) Arrott plots (H/M vs M2 ) of the 17, 28, and 43 nm samples. The red curve is the data at magnetic transition temperature (TC ); (d) Spontaneous magnetization as a function of temperature for the 17, 28, and 43 nm samples. Solid curve is the fitting data by using the power law form of .
(a)-(c) Temperature dependence of magnetic entropy change under different magnetic field changes of 0.5–4.5 T; (d) Field dependence of RCP for the selected 17, 28, and 43 nm samples.
Particle size D of La0.8Ca0.2MnO3 sample annealed at different temperatures Tanneal .
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