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Fig. 7. Magnetic susceptibility (7) versus temperature (T) plots for MnO, obtained by decomposition of MnC204.2H20 in N2 environment at (a) 500°C and (b) 600°C for 5 heach under the zero-field-cooled (ZFC) and field-cooled (FC) conditions. These reveal presence of Mn30, phase as well. The Néel temperature of MnO as ~120K is clearly seen in the insets.

Figure 7 Magnetic susceptibility (7) versus temperature (T) plots for MnO, obtained by decomposition of MnC204.2H20 in N2 environment at (a) 500°C and (b) 600°C for 5 heach under the zero-field-cooled (ZFC) and field-cooled (FC) conditions. These reveal presence of Mn30, phase as well. The Néel temperature of MnO as ~120K is clearly seen in the insets.

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Fig. 1. Weight percent (W (%)) versus temperature (T) and dW/dT versus T plots of manganese oxalate dihydrate in (a) oxygen and (b) air ambient.
Fig. 1. Weight percent (W (%)) versus temperature (T) and dW/dT versus T plots of manganese oxalate dihydrate in (a) oxygen and (b) air ambient.
Fig. 2. XRD patterns of (a) Mn20s3 (b.c.c.) resulting by decomposition of manganese oxalate dihydrate at 750°C for 3h under oxygen ambient (the inset shows the cor- responding Williamson-Hall (6 cos @ versus sin@) plot) and (b) mixture of Mn203, Mns0g and Mn30, phases emerged by decomposition of MnC20,4-:2H20 at 500°C for 2h in air.
Fig. 2. XRD patterns of (a) Mn20s3 (b.c.c.) resulting by decomposition of manganese oxalate dihydrate at 750°C for 3h under oxygen ambient (the inset shows the cor- responding Williamson-Hall (6 cos @ versus sin@) plot) and (b) mixture of Mn203, Mns0g and Mn30, phases emerged by decomposition of MnC20,4-:2H20 at 500°C for 2h in air.
Fig. 3. XRD patterns of manganese oxide powder obtained by decomposition of dried sol-gel product at 500°C and 600°C for 5h in (a) argon (Ar) and (b) nitro- gen (N2) environment, showing emergence of MnO alone or with small quantity of Mn304.
Fig. 3. XRD patterns of manganese oxide powder obtained by decomposition of dried sol-gel product at 500°C and 600°C for 5h in (a) argon (Ar) and (b) nitro- gen (N2) environment, showing emergence of MnO alone or with small quantity of Mn304.
Fig. 4. Typical scanning electron micrographs (in SE mode) of (a) manganese oxalate dihydrate and (b) Mn203, obtained by the decomposition of oxalate at 750°C for 3h ir oxygen ambient.
Fig. 4. Typical scanning electron micrographs (in SE mode) of (a) manganese oxalate dihydrate and (b) Mn203, obtained by the decomposition of oxalate at 750°C for 3h ir oxygen ambient.
Fig. 5. Scanning electron micrographs of Mn203, obtained by decomposition of oxalate in air for 2h each at (a) 300°C, (b and c) 500°C and (d-f) MnO formed at 600°C for 5h in Np. Note spherical beads/cluster like morphology with each bead made of nano-size particles.
Fig. 5. Scanning electron micrographs of Mn203, obtained by decomposition of oxalate in air for 2h each at (a) 300°C, (b and c) 500°C and (d-f) MnO formed at 600°C for 5h in Np. Note spherical beads/cluster like morphology with each bead made of nano-size particles.
4 Present in small quantity. > More quantity than observed in case of N2 at 600°C for 2h Formation of various manganese oxides by decomposition of sol-gel derived manganese oxalate dihydrate in oxygen, air, nitrogen and argon ambient Table 1
4 Present in small quantity. > More quantity than observed in case of N2 at 600°C for 2h Formation of various manganese oxides by decomposition of sol-gel derived manganese oxalate dihydrate in oxygen, air, nitrogen and argon ambient Table 1
Fig. 6. Temperature dependence of the magnetic susceptibility (7) for Mn203, obtained after decomposition of MnC204-2H20 in air at 500°C for 2h (a) under zero-field-cooled (ZFC) and field-cooled (FC) conditions and (b) enlarged view of ZFC curve in low temperature regime depicting a maximum at ~12 K. The inset of figure (a) shows peaks clearly at 79 K and 131 K corresponding to the Neel temperature of Mn203 and MnsOg, respectively.
Fig. 6. Temperature dependence of the magnetic susceptibility (7) for Mn203, obtained after decomposition of MnC204-2H20 in air at 500°C for 2h (a) under zero-field-cooled (ZFC) and field-cooled (FC) conditions and (b) enlarged view of ZFC curve in low temperature regime depicting a maximum at ~12 K. The inset of figure (a) shows peaks clearly at 79 K and 131 K corresponding to the Neel temperature of Mn203 and MnsOg, respectively.
Fig.9. Magnetization versus field (M-H) plots of Mn203 formed by decomposition of oxalate at 750°C for 3 hin oxygen ambient. The hysteresis loop in the inset indicates the presence of a ferromagnetic phase. Fig. 8. The d(xzrcT)/dT versus T plots of products formed by decomposition of man- ganese oxalate dihydrate in (a) air at 500°C for 2h, oxygen (at 750°C for 3h) and nitrogen ambient at 600°C for 5h showing Néel temperatures of 75K (Mn203), 130K (Mns50g), 115K (MnO), (b) air at 500°C for 2h, depicting orthorhombic to cubic transition of Mn203 at 310K.
Fig.9. Magnetization versus field (M-H) plots of Mn203 formed by decomposition of oxalate at 750°C for 3 hin oxygen ambient. The hysteresis loop in the inset indicates the presence of a ferromagnetic phase. Fig. 8. The d(xzrcT)/dT versus T plots of products formed by decomposition of man- ganese oxalate dihydrate in (a) air at 500°C for 2h, oxygen (at 750°C for 3h) and nitrogen ambient at 600°C for 5h showing Néel temperatures of 75K (Mn203), 130K (Mns50g), 115K (MnO), (b) air at 500°C for 2h, depicting orthorhombic to cubic transition of Mn203 at 310K.
Fig. 10. (a) XRD pattern and (b) xzrc(T) and xrc(T) curves of pure Mn304 powder obtained by calcination of oxalate at 1100°C for 4h in air. The inset of (b) shows the magnetization versus field plot at 10K.
Fig. 10. (a) XRD pattern and (b) xzrc(T) and xrc(T) curves of pure Mn304 powder obtained by calcination of oxalate at 1100°C for 4h in air. The inset of (b) shows the magnetization versus field plot at 10K.
Related topics:
EngineeringSol Gel ProcessCurie temperatureManganese OxideGel GrowthThermo Gravimetric Analysis
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