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Title: Coexistence of Haldane-gap excitations and long-range antiferromagnetic order in mixed-spin nickelates R{sub 2}BaNiO{sub 5}

Abstract

The spin dynamics of the S=1 Ni chains in mixed-spin antiferromagnets Pr{sub 2}BaNiO{sub 5} and Nd{sub x}Y{sub 2{minus}x}BaNiO{sub 5} is described in terms of a simple Ginzburg-Landau Lagrangian coupled to the sublattice of rare-earth ions. Within this framework we obtain a theoretical explanation for the experimentally observed coexistence of Haldane-gap excitations and long-range magnetic order, as well as for the increase of the Haldane-gap energy below the N{acute e}el point. We also predict that the degeneracy of the Haldane triplet is lifted in the magnetically ordered phase. The growth of both gaps are shown to follow from the magnon repulsion. The theoretical results are consistent with the available experimental data. {copyright} {ital 1998} {ital The American Physical Society}

Authors:
;  [1]
  1. Physics Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)
Publication Date:
OSTI Identifier:
565868
Resource Type:
Journal Article
Journal Name:
Physical Review, B: Condensed Matter
Additional Journal Information:
Journal Volume: 57; Journal Issue: 1; Other Information: PBD: Jan 1998
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANTIFERROMAGNETIC MATERIALS; NEEL TEMPERATURE; GINZBURG-LANDAU THEORY; ENERGY GAP; SPIN; MAGNONS; MAGNETIC PROPERTIES; BARIUM OXIDES; NICKEL OXIDES; YTTRIUM OXIDES; PRASEODYMIUM OXIDES; ANTIFERROMAGNETISM

Citation Formats

Maslov, S, and Zheludev, A. Coexistence of Haldane-gap excitations and long-range antiferromagnetic order in mixed-spin nickelates R{sub 2}BaNiO{sub 5}. United States: N. p., 1998. Web. doi:10.1103/PhysRevB.57.68.
Maslov, S, & Zheludev, A. Coexistence of Haldane-gap excitations and long-range antiferromagnetic order in mixed-spin nickelates R{sub 2}BaNiO{sub 5}. United States. doi:10.1103/PhysRevB.57.68.
Maslov, S, and Zheludev, A. Thu . "Coexistence of Haldane-gap excitations and long-range antiferromagnetic order in mixed-spin nickelates R{sub 2}BaNiO{sub 5}". United States. doi:10.1103/PhysRevB.57.68.
@article{osti_565868,
title = {Coexistence of Haldane-gap excitations and long-range antiferromagnetic order in mixed-spin nickelates R{sub 2}BaNiO{sub 5}},
author = {Maslov, S and Zheludev, A},
abstractNote = {The spin dynamics of the S=1 Ni chains in mixed-spin antiferromagnets Pr{sub 2}BaNiO{sub 5} and Nd{sub x}Y{sub 2{minus}x}BaNiO{sub 5} is described in terms of a simple Ginzburg-Landau Lagrangian coupled to the sublattice of rare-earth ions. Within this framework we obtain a theoretical explanation for the experimentally observed coexistence of Haldane-gap excitations and long-range magnetic order, as well as for the increase of the Haldane-gap energy below the N{acute e}el point. We also predict that the degeneracy of the Haldane triplet is lifted in the magnetically ordered phase. The growth of both gaps are shown to follow from the magnon repulsion. The theoretical results are consistent with the available experimental data. {copyright} {ital 1998} {ital The American Physical Society}},
doi = {10.1103/PhysRevB.57.68},
journal = {Physical Review, B: Condensed Matter},
number = 1,
volume = 57,
place = {United States},
year = {1998},
month = {1}
}