Magnetic material arrangement in oriented termites: a magnetic resonance study |
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Authors: | Alves O C Wajnberg E De Oliveira J F Esquivel D M S |
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Institution: | aDept de Fı́sico-Quı́mica, Universidade Federal Fluminense, Niterói, Rio de Janeiro, 14020-150, Brazil;bCentro Brasileiro de Pesquisas Fı́sicas, Rio de Janeiro, 22290-180, Brazil |
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Abstract: | Temperature dependence of the magnetic resonance is used to study the magnetic material in oriented Neocapritermes opacus (N.o.) termite, the only prey of the migratory ant Pachycondyla marginata (P.m.). A broad line in the g=2 region, associated to isolated nanoparticles shows that at least 97% of the magnetic material is in the termite’s body (abdomen + thorax). From the temperature dependence of the resonant field and from the spectral linewidths, we estimate the existence of magnetic nanoparticles 18.5 ± 0.3 nm in diameter and an effective magnetic anisotropy constant, Keff between 2.1 and 3.2 × 104 erg/cm3. A sudden change in the double integrated spectra at about 100 K for N.o. with the long body axis oriented perpendicular to the magnetic field can be attributed to the Verwey transition, and suggests an organized film-like particle system. |
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Keywords: | Magnetic material Orientation Termite Magnetic resonance |
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