Superparamagnetism is a form of magnetism which appears in small ferromagnetic or ferrimagnetic nanoparticles. In sufficiently small nanoparticles, magnetization can randomly flip direction under the influence of temperature. The typical time between two flips is called the Néel relaxation time. In the absence of an external magnetic field, when the time used to measure the magnetization of the nanoparticles is much longer than the Néel relaxation time, their magnetization appears to be in average zero; they are said to be in the superparamagnetic state. In this state, an external magnetic field is able to magnetize the nanoparticles, similarly to a paramagnet. However, their magnetic susceptibility is much larger than that of paramagnets.
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temperature. Superparamagnetism is different from this standard transition since it occurs below the Curie temperature of the material. Superparamagnetism occurs...
Magnetism is the class of physical attributes that occur through a magnetic field, which allows objects to attract or repel each other. Because both electric...
and there is often a blocking temperature at which a transition to superparamagnetism occurs. The spontaneous alignment of magnetic dipoles in ferromagnetic...
There are various other types of magnetism, such as spin glass, superparamagnetism, superdiamagnetism, and metamagnetism. Magnetic recording media: VHS...
large values for the Curie constants. These materials are known as superparamagnets. They are characterized by a strong ferromagnetic or ferrimagnetic...
thus lead to disorder in magnetic moments. The extreme of this is superparamagnetism which only occurs in small ferromagnetic particles. In this phenomenon...
particles, surface plasmon resonance in some metal particles, and superparamagnetism in magnetic materials. Nanoparticles exhibit a number of special properties...
material soft <50 nm for refractive index changes <100 nm for achieving superparamagnetism, mechanical strengthening or restricting matrix dislocation movement...
absence of an externally applied field and thus are often classified as "superparamagnets" rather than ferromagnets. In contrast to ferrofluids, magnetorheological...
induction tomography Magnetic induction MIT Magnetic particle imaging Superparamagnetism MPI 2005 Magnetic resonance imaging or nuclear magnetic resonance...
Lanci, L.; Kent, D. V. (2006). "Meteoric smoke fallout revealed by superparamagnetism in Greenland ice". Geophysical Research Letters. 33 (13): L13308....
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