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Title: Composite quantum spin liquid in a low-dimensional organometallic magnet

Abstract

The quantum magnet dimethylammonium trichlorocuprate (DMACuCl$$_3$$)has been considered an alternating antiferromagnetic-ferromagnetic (AFM-FM) chain along the $a$-axis, weakly coupled dimers along the $a$-axis and even a collection of isolated FM and AFM dimers. However, no spectroscopic probes have been applied until now to elucidate the underlying nature of the magnetic excitations. We present single crystal inelastic neutron scattering (INS) measurements that clearly indicate the magnetic excitations in DMACuCl$$_3$$ propagate along the $b$-axis. The spectrum has a gap $$\Delta = 0.95(2)$$ meV and bandwidth of $0.71(2)$ meV with excitations characteristic of a quasi-1-dimensional alternating AFM-FM exchange chain. Values of exchange constants place DMACuCl$$_3$$ in a limit interpolating between coupled AFM $$S=\frac{1}{2}$$ dimers and the $S=1$ Haldane chain. In order to consistently describe thermodynamic measurements with our spectroscopic results and the low-temperature crystal structure, we propose a composite two chain model where spin-spin interactions in one of the chains are very weakly correlated.

Authors:
 [1];  [2];  [1];  [1];  [1];  [3];  [4];  [1]
  1. ORNL
  2. University of Tennessee, Knoxville (UTK)
  3. National Institute of Standards and Technology (NIST)
  4. Florida State University
Publication Date:
Research Org.:
High Flux Isotope Reactor; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
932026
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 99
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CHAINS; CRYSTAL STRUCTURE; DIMERS; J-J COUPLING; MAGNETS; MONOCRYSTALS; NEUTRONS; PROBES; SCATTERING; SPIN; THERMODYNAMICS

Citation Formats

Stone, Matthew B, Tian, W., Lumsden, Mark D, Granroth, Garrett E, Mandrus, David, Chung, J.-H., Harrison, N., and Nagler, Stephen E. Composite quantum spin liquid in a low-dimensional organometallic magnet. United States: N. p., 2007. Web. doi:10.1103/PhysRevLett.99.087204.
Stone, Matthew B, Tian, W., Lumsden, Mark D, Granroth, Garrett E, Mandrus, David, Chung, J.-H., Harrison, N., & Nagler, Stephen E. Composite quantum spin liquid in a low-dimensional organometallic magnet. United States. doi:10.1103/PhysRevLett.99.087204.
Stone, Matthew B, Tian, W., Lumsden, Mark D, Granroth, Garrett E, Mandrus, David, Chung, J.-H., Harrison, N., and Nagler, Stephen E. Mon . "Composite quantum spin liquid in a low-dimensional organometallic magnet". United States. doi:10.1103/PhysRevLett.99.087204.
@article{osti_932026,
title = {Composite quantum spin liquid in a low-dimensional organometallic magnet},
author = {Stone, Matthew B and Tian, W. and Lumsden, Mark D and Granroth, Garrett E and Mandrus, David and Chung, J.-H. and Harrison, N. and Nagler, Stephen E},
abstractNote = {The quantum magnet dimethylammonium trichlorocuprate (DMACuCl$_3$)has been considered an alternating antiferromagnetic-ferromagnetic (AFM-FM) chain along the $a$-axis, weakly coupled dimers along the $a$-axis and even a collection of isolated FM and AFM dimers. However, no spectroscopic probes have been applied until now to elucidate the underlying nature of the magnetic excitations. We present single crystal inelastic neutron scattering (INS) measurements that clearly indicate the magnetic excitations in DMACuCl$_3$ propagate along the $b$-axis. The spectrum has a gap $\Delta = 0.95(2)$ meV and bandwidth of $0.71(2)$ meV with excitations characteristic of a quasi-1-dimensional alternating AFM-FM exchange chain. Values of exchange constants place DMACuCl$_3$ in a limit interpolating between coupled AFM $S=\frac{1}{2}$ dimers and the $S=1$ Haldane chain. In order to consistently describe thermodynamic measurements with our spectroscopic results and the low-temperature crystal structure, we propose a composite two chain model where spin-spin interactions in one of the chains are very weakly correlated.},
doi = {10.1103/PhysRevLett.99.087204},
journal = {Physical Review Letters},
number = ,
volume = 99,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}