Uses And Properties Of Magnetic Nannoparticles (MNP)

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Magnetic nanoparticles (MNP) are a class of nanoparticles which can be manipulated using magnetic field. Such particles usually consist of magnetic elements such as iron, nickel and cobalt and their chemical compounds. The surface of MNPs is often modified by surfactants, silicones, phosphoric acids to make them stable in solution. Even the surface is often passivated by a gentle oxide coating which are diamagnetic (e.g., CoO coating over Co NPs).
The properties of MNPs not only depend on size and shape but also depend on synthesis method, chemical composition, type and degree of defects of the crystal lattice, interaction of the particles with the surrounding materials, and the neighbor particles. MNPs show different properties from atoms and bulk materials, because these MNPs have very high magnetic anisotropy with different Néel (TN) and Curie (TC) temperatures . By tuning all the properties mentioned earlier, properties of the MNPs can be manipulated.
3.2. Suitability of MNP as biosensors: MNPs have many unique advantages as a biosensor. The size and properties of MNPs can be easily controlled and this enables them to be used in …show more content…

Magnetic particles in a liquid, with magnetic moments aligned by an applied magnetic field, employ two relaxation mechanisms when magnetic field is turned off: (i) Brownian relaxation and (ii) Néel relaxation. Brownian relaxation is governed by the physical rotation of the entire particle and characterized by the Brownian relaxation time, tB. The Brownian relaxation is much faster than the Néel relaxation. For the NPs, when the applied field is removed, the magnetization vector within the particle returns to the lowest energy state along the easy axis with a characteristic Néel relaxation time, tN. The characteristic Néel Relaxation time is used for detection of targeted

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