Nonequilibrium multiple transitions in the core-shell Ising nanoparticles driven by randomly varying magnetic fields

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VATANSEVER E., Acharyya M.

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, cilt.527, 2021 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 527
  • Basım Tarihi: 2021
  • Doi Numarası: 10.1016/j.jmmm.2020.167721
  • Dergi Adı: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Chemical Abstracts Core, Communication Abstracts, INSPEC, Metadex, Civil Engineering Abstracts
  • Anahtar Kelimeler: Magnetic hyperthermia, Core/shell nanoparticles, Monte Carlo simulation, Dynamic phase transitions, 2ND-ORDER PHASE-TRANSITIONS, CRITICAL-BEHAVIOR, MODEL, DIAGRAM, INSTABILITY, SURFACE, POINTS
  • Dokuz Eylül Üniversitesi Adresli: Evet

Özet

The nonequilibrium behaviour of a core-shell nanoparticle has been studied by Monte-Carlo simulation. The core consists of Ising spins of sigma = 1/2 and the shell contains Ising spins of S = 1. The interactions within the core and in the shell are considered ferromagnetic but the interfacial interaction between core and shell is antiferro-magnetic. The nanoparticle system is kept in open boundary conditions and is driven by randomly varying (in time but uniform over the space) magnetic field. Depending on the width of the randomly varying field and the temperature of the system, the core, shell and total magnetization varies in such a manner that the time averages vanish for higher magnitude of the width of random field, exhibiting a dynamical symmetry breaking transitions. The susceptibilities get peaked at two different temperatures indicating nonequilibrium multiple transitions. The phase boundaries of the nonequilibrium multiple transitions are drawn in the plane formed by the axes of temperature and the width of the randomly varying field. Furthermore, the effects of the core and shell thicknesses on the multiple transitions have been discussed.