Motivated by recent experimental results in ultrathin helimagnetic holmium films, we have performed an extensive classical Monte Carlo simulation of films of different thickness, assuming a Hamiltonian with six interlayer exchange constants. Both magnetic structure and critical properties have been analyzed. For n>16, n being the number of spin layers in the film, a correct bulk limit is reached, while for lower n the film properties are clearly affected by the strong competition among the helical pitch and the surface effects, which involve the majority of the spin layers. In the thickness range n=9−16 three different magnetic phases emerge, with the high-temperature, disordered, paramagnetic phase and the low-temperature, long-range ordered one separated by an intriguing intermediate-temperature block phase, where outer ordered layers coexist with some inner disordered ones. The phase transition of these inner layers displays the signatures of a Kosterlitz- Thouless one. Finally, for n<=7 the film collapses once and for all to a quasicollinear order. A comparison of our Monte Carlo simulation outcomes to available experimental data is also proposed and further experimental investigations are suggested.

Monte Carlo simulations of rare-earth holmium ultrathin films / F. Cinti; A. Cuccoli; A. Rettori. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - STAMPA. - 79:(2009), pp. 134420:1-134420:11. [10.1103/PhysRevB.79.134420]

Monte Carlo simulations of rare-earth holmium ultrathin films

CINTI, FABIO;CUCCOLI, ALESSANDRO;RETTORI, ANGELO
2009

Abstract

Motivated by recent experimental results in ultrathin helimagnetic holmium films, we have performed an extensive classical Monte Carlo simulation of films of different thickness, assuming a Hamiltonian with six interlayer exchange constants. Both magnetic structure and critical properties have been analyzed. For n>16, n being the number of spin layers in the film, a correct bulk limit is reached, while for lower n the film properties are clearly affected by the strong competition among the helical pitch and the surface effects, which involve the majority of the spin layers. In the thickness range n=9−16 three different magnetic phases emerge, with the high-temperature, disordered, paramagnetic phase and the low-temperature, long-range ordered one separated by an intriguing intermediate-temperature block phase, where outer ordered layers coexist with some inner disordered ones. The phase transition of these inner layers displays the signatures of a Kosterlitz- Thouless one. Finally, for n<=7 the film collapses once and for all to a quasicollinear order. A comparison of our Monte Carlo simulation outcomes to available experimental data is also proposed and further experimental investigations are suggested.
79
134420:1
134420:11
F. Cinti; A. Cuccoli; A. Rettori
File in questo prodotto:
File Dimensione Formato  
CCR09.pdf

Accesso chiuso

Tipologia: Versione finale referata (Postprint, Accepted manuscript)
Licenza: DRM non definito
Dimensione 521.69 kB
Formato Adobe PDF
521.69 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2158/357800
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 8
  • ???jsp.display-item.citation.isi??? 8
social impact