A Au80Fe20 film was deposited on Si substrates by DC magnetron co-sputtering in Ar atmosphere. Magnetic quantities (isothermal magnetisation, initial and high-field susceptibilities, FC/ZFC curves) were obtained between 10 and 400 K using an extraction method and vibrating-sample magnetometry. Magnetisation curves exhibit an apparent superparamagnetic behaviour with a small hysteresis which disappears above 270 K. FC/ZFC curves become separate below 50 K. Anhysteretic curves are fitted by a Langevin function with a single, temperature-dependent magnetic moment. The measurements are consistent with a picture of the film as a granular system containing interacting Fe nanoparticles. At 400 K, the atomic magnetic moments inside Fe nanoparticles experience a ferromagnetic-to-paramagnetic transition. (c) 2004 Elsevier B.V. All rights reserved.
Temperature dependence of spontaneous magnetisation in granular Au80Fe20 films
DA RE, Andrea;RONCONI, Franco;SPIZZO, Federico;
2005
Abstract
A Au80Fe20 film was deposited on Si substrates by DC magnetron co-sputtering in Ar atmosphere. Magnetic quantities (isothermal magnetisation, initial and high-field susceptibilities, FC/ZFC curves) were obtained between 10 and 400 K using an extraction method and vibrating-sample magnetometry. Magnetisation curves exhibit an apparent superparamagnetic behaviour with a small hysteresis which disappears above 270 K. FC/ZFC curves become separate below 50 K. Anhysteretic curves are fitted by a Langevin function with a single, temperature-dependent magnetic moment. The measurements are consistent with a picture of the film as a granular system containing interacting Fe nanoparticles. At 400 K, the atomic magnetic moments inside Fe nanoparticles experience a ferromagnetic-to-paramagnetic transition. (c) 2004 Elsevier B.V. All rights reserved.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
