Phase transitions in a ferromagnet with an anisotropic biquadratic exchange interaction

2006 ◽  
Vol 32 (3) ◽  
pp. 214-223 ◽  
Author(s):  
Yu. A. Fridman ◽  
O. A. Kosmachev ◽  
F. N. Klevets
Keyword(s):  
Phase Transitions ◽  
Exchange Interaction ◽  
Biquadratic Exchange ◽  
Biquadratic Exchange Interaction

Field-Induced Phase Transition in S=1 XXZ Chain with Biquadratic Exchange Interaction

1997 ◽  
Vol 11 (30) ◽  
pp. 1295-1302 ◽  
Author(s):  
Ryutaro Sato
Keyword(s):  
Phase Transition ◽  
Exchange Interaction ◽  
Lattice Gas ◽  
Finite Size ◽  
Approximate Solutions ◽  
Biquadratic Exchange ◽  
Nested Bethe Ansatz ◽  
Xxz Chain ◽  
Biquadratic Exchange Interaction ◽  
The Magnetic Field

We study the magnetization process of the S=1 XXZ chain with biquadratic exchange interaction at zero temperature. This system can be regarded as a quantum lattice gas composed of "particles" with Sz=0, ±1. We introduce an approximate nested Bethe ansatz (ANBA) to examine the possibility of phase transition induced by the magnetic field. In the high-magnetization region σ≥σ0 for certain σ0, the ANBA gives the exact ground state energies. For σ<σ0 the ANBA gives approximate solutions. The analysis shows that a phase transition occurs at σ0 across which the magnetic susceptibility changes discontinuously. Comparing with the finite-size diagonalization, we argue that σ0 is the exact critical magnetization.

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