Tejada Palacios, JavierBalcells i Argemí, LluísLinderoth, S. (Soren)Perzynski, R.Rigau, B.Barbara, B.Bacri, J. C. (Jean Claude)2012-02-162012-02-1619930021-8979https://hdl.handle.net/2445/22092We present a study of the magnetic relaxation of several ferrofluids composed of particles of about 40 Å in diameter (Fe3O4FeC, CoFe2O4). Our key observation is a nonthermal character of the relaxation below 3 K for the CoFe2O4 ferrofluid and below 1 K for the FeC ferrofluid. The crossover temperature from thermal to nonthermal (quantum) regime is in accordance with theoretical suggestions of macroscopic quantum tunneling of magnetization in single doma in particles3 p.application/pdfeng(c) American Institute of Physics, 1993Relaxació magnèticaMagnetismeEfecte túnelMatèria condensadaAnisotropiaMagnetic relaxationMagnetismTunneling (Physics)Condensed matterAnisotropyinfo:eu-repo/semantics/article3625info:eu-repo/semantics/openAccess