Publication Date

10-1-2019

Department

Ames Laboratory; Physics and Astronomy

Campus Units

Ames Laboratory, Physics and Astronomy

OSTI ID+

1572382

Report Number

IS-J 10064

DOI

10.1103/PhysRevB.100.144433

Journal Title

Physical Review B

Volume Number

100

Issue Number

14

First Page

144433

Abstract

Structural and magnetic properties of a quasi-one-dimensional spin-1/2 compound NaVOPO4 are explored by x-ray diffraction, magnetic susceptibility, high-field magnetization, specific heat, electron spin resonance, and 31P nuclear magnetic resonance measurements, as well as complementary ab initio calculations. Whereas magnetic susceptibility of NaVOPO4 may be compatible with the gapless uniform spin chain model, detailed examination of the crystal structure reveals a weak alternation of the exchange couplings with the alternation ratio α≃0.98 and the ensuing zero-field spin gap Δ0/kB≃2.4K directly probed by field-dependent magnetization measurements. No long-range order is observed down to 50 mK in zero field. However, applied fields above the critical field Hc1≃1.6T give rise to a magnetic ordering transition with the phase boundary TN∝(H−Hc1)1ϕ, where ϕ≃1.8 is close to the value expected for Bose-Einstein condensation of triplons. With its weak alternation of the exchange couplings and small spin gap, NaVOPO4 lies close to the quantum critical point.

DOE Contract Number(s)

37(3)/14/26/2017-BRNS; AC02-07CH11358

Language

en

Department of Energy Subject Categories

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Publisher

Iowa State University Digital Repository, Ames IA (United States)

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