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Polydispersity-linked Memory Effects in a Magnetic Nanoparticle System

1. S. Chakraverty·2. A. Frydman·3. M. Bandyopadhyay·4. S. Dattagupta·5. Surajit Sengupta 6. P. A. Sreeram
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Abstract

We have performed a series of measurements on the low temperature behavior of a magnetic nano-particle system. Our results show striking memory effects in the dc magnetization. Dipolar interactions among the nano-particles {\em suppress} the memory effect. We explain this phenomenon by the superposition of different super paramagnetic relaxation times of single domain magnetic nano- particles. Moreover, we observe a crossover in the temperature dependence of coercivity. We show that a dilute dispersion of particles with a flat size distribution yields the best memory.

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1. S. Chakraverty, 2. A. Frydman, 3. M. Bandyopadhyay, 4. S. Dattagupta, 5. Surajit Sengupta 6. P. A. Sreeram. 2004-07-08. Polydispersity-linked Memory Effects in a Magnetic Nanoparticle System. https://arxiv.org/abs/cond-mat/0407202

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