Improved Coercivity of Solvothermally Grown Hematite (α‐Fe₂O₃) and Hematite/Graphene Oxide Nanocomposites (α‐Fe₂O₃/GO) at Low Temperature

Abstract

α‐Fe2O3 and α‐Fe2O3/graphene oxide (GO) nanocomposites are synthesized by solvothermal method in acetonitrile medium at 200 °C. XRD studies reveals the formation of α‐Fe2O3 and α‐Fe2O3/GO nanocomposites. Raman studies indicate that GO in α‐Fe2O3/GO system was more disordered than GO. The enhanced low temperature magnetic saturation and coercivity in α‐Fe2O3 and α‐Fe2O3/GO are related to frozen canted spins. Blocking temperature of α‐Fe2O3/GO is 348 K, which also shows higher coercivity of the order of about 3064 Oe at 5 K. The α‐Fe2O3/GO composite exhibits thermal hysteresis at Morin transition (ΔTM = 11 K).

Activated Carbon Obtained from Bamboo: Synthesis, Morphological, Vibrational, and Electrical Properties and Possible Temperature Sensor

“…All samples exhibit two Raman bands centered at 1323 and 1593 cm −1 , respectively, the first wider than the second. These two bands, D (disordered induced band) correspond to the vibration of the plane of the carbon sp 2 bonds in structural imperfections and G (graphite Raman band) the vibration of the plane of the sp 2 bond for crystalline areas, agreeing with recent reports . Besides, only in the AC‐573 sample, it is possible to observe in Figure a that the D1 band located at 1432 cm −1 exhibits systematic vibrational behavior of the typical amorphous carbon .…”

Magnetic properties of hematite (α − Fe2O3) nanoparticles synthesized by sol-gel synthesis method: The influence of particle size and particle size distribution

“…This sharp jump and behavior of the magnetization is the property of α − Fe 2 O 3 phase and is called the Morin transition [52,53]. Moreover, a blocking temperature at about 50 K that originates from the α − Fe 2 O 3 nanoparticles is also visible in the ZFC curve, thus indicating the presence of the nanoparticles with smaller sizes.…”

“…On the other hand, for the ferromagnetic particles typical properties are the remanent magnetization (M r > 0 ) and coercivity (H C > 0 ). The M (T ) of hematite may display three interesting temperatures for investigation: the Néel temperature, the Morin temperature, and the blocking temperature [41][42][43][52][53][54][55]. The measured M (T ) dependence for the sample is shown in Fig.…”

Hydrothermal Synthesis of Hematite Nanoparticles Decorated on Carbon Mesospheres and Their Synergetic Action on the Thermal Decomposition of Nitrocellulose

“…Hematite (α-Fe 2 O 3 ) nanoparticles, one of the most stable phases of iron oxide which is an n-type semiconductor [ 18 ], have received a particular attention owing to their interesting properties and their wide range of application fields in various industrial reactions such as catalysis and biotechnology [ 19 ], lithium-ion batteries [ 20 ], gas sensing, magnetic memory, biological uses and degradation of organic contaminants [ 18 ]. α-Fe 2 O 3 nanoparticles can be synthesized with various shapes like nano-platelets, nano-belts, nano-rods, nano-cubes, and nanotubes utilizing miscellaneous physicochemical methodologies [ 20 , 21 , 22 , 23 , 24 ].…”