We consider polymers made of magnetic monomers (Ising or Heisenberg-like) in a good solvent. These polymers are modeled as self-avoiding walks on a cubic lattice, and the ferromagnetic interaction between the spins carried by the monomers is short-ranged in space. At low temperature, these polymers undergo a magnetic induced first order collapse transition, that we study at the mean field level. Contrasting with an ordinary Theta point, there is a strong jump in the polymer density, as well as in its magnetization. In thr presence of a magnetic field, the collapse temperature increases: while the discontinuities decrease. Beyond a multicritical point, the transition becomes second order and Theta-like. Monte Carlo simulations for the Ising case are in qualitative agreement with these results.
Phase diagram of magnetic polymers
ORLANDINI, ENZO
1999
Abstract
We consider polymers made of magnetic monomers (Ising or Heisenberg-like) in a good solvent. These polymers are modeled as self-avoiding walks on a cubic lattice, and the ferromagnetic interaction between the spins carried by the monomers is short-ranged in space. At low temperature, these polymers undergo a magnetic induced first order collapse transition, that we study at the mean field level. Contrasting with an ordinary Theta point, there is a strong jump in the polymer density, as well as in its magnetization. In thr presence of a magnetic field, the collapse temperature increases: while the discontinuities decrease. Beyond a multicritical point, the transition becomes second order and Theta-like. Monte Carlo simulations for the Ising case are in qualitative agreement with these results.Pubblicazioni consigliate
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