Surface spin-flop and discommensuration transitions in antiferromagnets

Abstract

Phase diagrams as a function of anisotropy $D$ and magnetic field $H$ are obtained for discommensurations and surface states for an antiferromagnet in which $H$ is parallel to the easy axis, by modeling it using the ground states of a one-dimensional chain of classical XY spins. A surface spin-flop phase exists for all $D$, but the interval in $H$ over which it is stable becomes extremely small as $D$ goes to zero. First-order transitions, separating different surface states and ending in critical points, exist inside the surface spin-flop region. They accumulate at a field $H^{\prime }$ (depending on $D$) significantly less than the value $H_{SF}$ for a bulk spin-flop transition. For $H^{\prime }<H<H_{SF}$ there is no surface spin-flop phase in the strict sense; instead, the surface restructures by, in effect, producing a discommensuration infinitely far away in the bulk. The results are used to explain in detail the phase transitions occurring in systems consisting of a finite, even number of layers.

Revtex 17 pages, 15 figures

References in corpus (4)

• Surface spin-flop phases and bulk discommensurations in antiferromagnets
• Spin Softening in Models with Competing Interactions: A New High Anisotropy Expansion to All Orders
• Lifting of Multiphase Degeneracy by Quantum Fluctuations
• The Role of Spin Anisotropy in the Unbinding of Interfaces

Cited by in corpus (5)

• Reorientation in Antiferromagnetic Multilayers: Spin-Flop Transition and Surface Effects
• Surface spin-flop transition in a uniaxial antiferromagnetic Fe/Cr superlattice induced by a magnetic field of arbitrary direction
• Smeared spin-flop transition in random antiferromagnetic Ising chain
• Solitons in a discrete model of chiral liquid crystals with competing interactions
• Field-induced inhomogeneous ground states of antiferromagnetic ANNNI chains