Hobbies And Interests
Mechanism of Superparamagnetism
Magnetic energy of nanoparticles is a factor of the magnestic anistropic constant, volume and thermal energy. When the spin flips, the net magnetism is zero, at which point it is in a state of superparamagnetism. Nanoparticles must achieve a local minimum and temperature must reach a local maximum for the magnetic change to occur.
Magnetization Curve
Superparamegnetic behavior can be represented as an S-curve, where magnetic motion and energy barrier represent the x and y axes, respectively. The "macro-spin moment" is the point in time just prior to the inversion. If particles revert to their original state (i.e., flip again), the time between the first and second flips is known as the Neel relaxation time, which can be several milliseconds or a theoretically infinite length of time.
Practical Applications
Superparamagnetic behavior is not just an abstract topic of study in advanced physics. It also has practical applications. In the medical field, superparamagnetism is used in MRI technology, DNA and RNA experimentation, treatment of acute hyperthermia and drug delivery. It's also used in high-tech sensors (of the sort used in aerospace technology) and other aspects of nanotechnology.
Other Characteristics of Superparamagnetic Behavior
The larger a nanoparticle, the greater its magnetic permeability. The time-variance of the paramagnetic field is represented in the equation f(x) = 1 / tan g(x) ' 1 / x, where 1/T indicates the direction of spin. Adjacent clusters of nanoparticles tend to synchronize in their spin.