Influence of magnetic anisotropy and dipolar interactions on magnetocaloric effect in nanostructured materials

✍ Scribed by Prida, Victor M. ;Vega, Victor ;Serantes, David ;Baldomir, Daniel ;Ilyn, Maxim ;Zhukov, Arcady P. ;González, Julián ;Hernando, Blanca

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 773 KB
• Volume: 206
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200881731

✦ Synopsis

Abstract

We outline the magnetic and magnetocaloric behaviour of magnetic nanoparticles distributed into columnar‐like arrangements with their easy axes collinear aligned along the chain direction, and comparing to that of ferromagnetic nanowires arrays. An extended Monte Carlo model taking into account the influence of both, the magnetic anisotropy and magnetostatic interactions of dipolar origin between ferromagnetic nanoparticles chains, has been developed. The existence of a maximum in thermomagnetic curves for applied magnetic fields up to 2.5 times the anisotropy field value of the system, and the coexistence of positive and negative magnetocaloric effect have been predicted confirming the experimental results found in highly ordered arrays of ferromagnetic nanowires.

Positive and negative MCE regimes in an array of single magnetic domain ferromagnetic nanowires and its dependence on the applied field value. The inset shows the MFM image of the magnetic monodomain dipole structure for an isolated Ni‐rich nanowire.

magnified image