Uniform Magnetic Order in a Ferromagnetic-Antiferromagnetic Random Alternating Quantum Spin Chain

Abstract

An $S=1/2$ ferromagnetic (F) - antiferromagnetic (AF) random alternating Heisenberg quantum spin chain model is investigated in connection to its realization compound: (CH${}_3$)${}_2$CHNH${}_3$Cu(Cl${}_x$Br${}_{1-x}$)${}_3$. The exchange interaction bonds have alternating strong F-AF random bonds and weak uniform AF bonds. Using the quantum Monte Carlo method we have found that the excitation energy gap closes and the uniform AF order becomes critical in the intermediate concentration region. This finding explains the experimental observation of the magnetic transition by considering weak interchain interactions. Present results suggest that the uniform AF order survives even in the presence of randomly located ferromagnetic bonds. This may be a new quantum effect.

arXiv comment9 pages, 11 figures

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Cited by in corpus (11)

• Muon spin relaxation and rotation study on the solid solution of the two spin-gap systems (CH3)2CHNH3-CuCl3 and (CH3)2CHNH3-CuBr3
• μSR-detection of the soft-mode toward the exotic magnetic ground state in bond-disordered quantum spin system IPA-Cu(Cl${}_{0.35}$Br${}_{0.65}$)${}_3$
• 1H-NMR Study on the Magnetic Order in the Mixture of Two Spin Gap Systems (CH3)2CHNH3CuCl3 and (CH3)2CHNH3CuBr3
• Nonequilibrium dynamic-correlation-length scaling method
• From measurements to inferences of physical quantities in numerical simulations
• Impurity-induced magnetic order in the mixture of two spin gap systems (CH3)2CHNH3CuCl3 and (CH3)2CHNH3CuBr3
• Studies on a frustrated Heisenberg spin chain with alternating ferromagnetic and antiferromagnetic exchanges
• Window measurements of simulations in random systems
• A strategy for solving difficulties in spin-glass simulations
• Renormalization-group investigation of the S=1 random antiferromagnetic Heisenberg Chain
• \muSR-dtected Soft mode toward a Possible Phase Transition in disordered spin gap system (CH3)2CHNH3-Cu(ClxBr1-x)3