Specific heat of defects in Haldane systems Y2BaNiO5 and NENP: Absence of free spin-1/2 excitations

A. P. Ramirez, S. W. Cheong, M. L. Kaplan

Research output: Contribution to journalArticle

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Abstract

We have measured the specific heat of the antiferromagnetic spin-1 chain compounds NENP and Y2BaNiO5 diluted with Zn, at temperatures between 0.1 and 15 K and magnetic fields up to 9 T. We find that the defect-related Schottky anomaly in Y2BaNi1-xZnxO5 is better described by assuming the defects are S=1, rather than free S=1/2, the latter proposed to exist within the valence-bond-solid model of finite S=1 chains. The relationship of these results to electron-spin-resonance data for NENP, which imply free S=1/2 defects is discussed.

Original languageEnglish (US)
Pages (from-to)3108-3111
Number of pages4
JournalPhysical review letters
Volume72
Issue number19
DOIs
StatePublished - Jan 1 1994

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specific heat
defects
excitation
electron paramagnetic resonance
anomalies
valence
magnetic fields
temperature

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

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Specific heat of defects in Haldane systems Y2BaNiO5 and NENP : Absence of free spin-1/2 excitations. / Ramirez, A. P.; Cheong, S. W.; Kaplan, M. L.

In: Physical review letters, Vol. 72, No. 19, 01.01.1994, p. 3108-3111.

Research output: Contribution to journalArticle

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T1 - Specific heat of defects in Haldane systems Y2BaNiO5 and NENP

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