Abstract In recent studies we find that three kinds of magnetization plateaux appear at one‐third of the saturation magnetization in the ground‐state magnetization curve of an anisotropic (S, S′) = (1, 2) spin‐alternating chain, in which S = 1 and S′ = 2 spins with on‐site anisotropies are alternatingly arranged and coupled antiferromagnetically. One of these plateaux is a quantum plateau, while the other two are classical plateaux. We here show that the first‐order phase transition between the two classical one‐third plateau states occurs when the on‐site anisotropy for the S = 1 spin is of easy‐axis type and its magnitude is sufficiently large. We numerically determine the phase transition line for this first‐order transition and briefly discuss the origin of its occurrence.Abstract In recent studies we find that three kinds of magnetization plateaux appear at one‐third of the saturation magnetization in the ground‐state magnetization curve of an anisotropic (S, S′) = (1, 2) spin‐alternating chain, in which S = 1 and S′ = 2 spins with on‐site anisotropies are alternatingly arranged and coupled antiferromagnetically. One of these plateaux is a quantum plateau, while the other two are classical plateaux. We here show that the first‐order phase transition between the two classical one‐third plateau states occurs when the on‐site anisotropy for the S = 1 spin is of easy‐axis type and its magnitude is sufficiently large. We numerically determine the phase transition line for this first‐order transition and briefly discuss the origin of its occurrence.

physica status solidi (b)Feb 15, 20101 citation

Quantum Magnetization Plateau of an Anisotropic Mixed Spin Chain

KIYOMI OKAMOTO

Jan 1, 20060 citations

Magnetization-plateau state of the S = 3 / 2 spin chain with single-ion anisotropy

Atsuhiro Kitazawa, Kiyomi Okamoto

We reexamine the numerical study of the magnetized state of the $S=3/2$ spin chain with single-ion anisotropy $D(>0)$ for the magnetization ${M=M}_{S}/3,$ where ${M}_{S}$ is the saturation magnetization. At this magnetization, we find that for $D<{D}_{c1}=0.387$ the system is critical and the magnetization plateau does not appear. For $D>{D}_{c1},$ the parameter region is divided into two parts ${D}_{c1}<D<{D}_{c2}=0.943$ and ${D}_{c2}<D.$ In each region, the system is gapful and the ${M=M}_{S}/3$ magnetization plateau appears in the magnetization process. From our numerical calculation, the intermediate region ${D}_{c1}<D<{D}_{c2}$ should be characterized by a magnetized valence-bond-solid state.We reexamine the numerical study of the magnetized state of the $S=3/2$ spin chain with single-ion anisotropy $D(>0)$ for the magnetization ${M=M}_{S}/3,$ where ${M}_{S}$ is the saturation magnetization. At this magnetization, we find that for $D<{D}_{c1}=0.387$ the system is critical and the magnetization plateau does not appear. For $D>{D}_{c1},$ the parameter region is divided into two parts ${D}_{c1}<D<{D}_{c2}=0.943$ and ${D}_{c2}<D.$ In each region, the system is gapful and the ${M=M}_{S}/3$ magnetization plateau appears in the magnetization process. From our numerical calculation, the intermediate region ${D}_{c1}<D<{D}_{c2}$ should be characterized by a magnetized valence-bond-solid state.

arXiv:cond-mat/9911364Physical review. B, Condensed matterJul 1, 200036 citations

We reexamine the numerical study of the magnetized state of the

S=3/2

spin chain with single-ion anisotropy

D(>0)

for the magnetization

{M=M}_{S}/3,

where

{M}_{S}

is the saturation magnetization. At this magnetization, we find that for

D<{D}_{c1}=0.387

the system is critical and the magnetization plateau does not appear. For

D>{D}_{c1},

the parameter region is divided into two parts

{D}_{c1}<D<{D}_{c2}=0.943

and

{D}_{c2}<D.

In each region, the system is gapful and the

{M=M}_{S}/3

magnetization plateau appears in the magnetization process. From our numerical calculation, the intermediate region

{D}_{c1}<D<{D}_{c2}

should be characterized by a magnetized valence-bond-solid state.