GAXRD patterns of Fe3O4 films grown at different substrate temperatures (Glancing angle −0.5°).
Raman spectra for all the film-samples deposited at 150, 175, 200, 225, and 250 °C recorded at room temperature in the range of 100–1000 cm−1.
R vs T dependence of all samples deposited at different temperatures. Only the 175 °C sample (Δ) shows the sharp change in R around 115 K. Curve (•) with arrow to the right shows the AC susceptibility vs T behavior of the 175 °C sample. Inset shows the ln(ρ) vs T−1/2 behavior of the 175 °C deposited sample with linear fit in the temperature range of 240–115 K and below in the vicinity of the Verwey transition.
The in-plane magnetization hysteresis loops of the 175 °C sample recorded at 300, 140, 115, 70, and 50 K. The inset shows the fitting (solid line in red) of the magnetization curve (filled square symbols) in the first quadrant using the M = MS (1 – b/Hn) corresponding to T = 300 K for this film sample.
The out-of-plane magnetization hysteresis loops measured on the 175 °C sample recorded at 300, 140, 115, 70, and 50 K.
Temperature dependence of the coercivity of the 175 °C deposited magnetite films obtained in H-parallel and H-perpendicular cases with respect to film plane. The change in the slope of coercivity around 115 K corresponds to the Verwey transition. The inset shows the variation of saturation moment, MS with temperature for this sample.
The room temperature in-plane and out-of-plane magnetization hysteresis loops measured on the sample deposited at 250 °C.
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