Shifted loops and coercivity from field-imprinted high-energy barriers in ferritin and ferrihydrite nanoparticles

J. O. Silva (1) , V.S. Amaral (1) , A. Urtizberea (2) , R. Bustamante (2) , A. Millán (2) , F. Palacio (2) , E. Kampert (3) , U. Zeitler (3) , Sophie de Brion (4) , O. Iglesias (5) , A. Labarta (5)

1 Department of Physics and CICECO
2 ICMA-CSIC - Instituto de Ciencia de Materiales de Aragón [Saragoza, España]
3 High Field Magnet Laboratory
4 NEEL - MagSup - Magnétisme et Supraconductivité
5 Barcelona and Institut de Nanoci'encia i Nanotecnologia

We show that the coercive field in ferritin and ferrihydrite depends on the maximum magnetic field in a hysteresis loop and that coercivity and loop shifts depend both on the maximum and cooling fields. In the case of ferritin, we show that the time dependence of the magnetization also depends on the maximum and previous cooling fields. This behavior is associated to changes in the intraparticle energy barriers imprinted by these fields. Accordingly, the dependence of the coercive and loop-shift fields with the maximum field in ferritin and ferrihydrite can be described within the frame of a uniform-rotation model considering a dependence of the energy barrier with the maximum and the cooling fields.

Domaines: Electrons fortement corrélés [cond-mat.str-el]

J. O. Silva, V.S. Amaral, A. Urtizberea, R. Bustamante, A. Millán, et al.. Shifted loops and coercivity from field-imprinted high-energy barriers in ferritin and ferrihydrite nanoparticles. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2011, 84, pp.104427. ⟨10.1103/PhysRevB.84.104427⟩. ⟨hal-01002333⟩