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Modified spin-wave study of random antiferromagnetic-ferromagnetic spin chains

Xin Wan·Kun Yang·R. N. Bhatt
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Abstract

We study the thermodynamics of one-dimensional quantum spin-1/2 Heisenberg ferromagnetic system with random antiferromagnetic impurity bonds. In the dilute impurity limit, we generalize the modified spin-wave theory for random spin chains, where local chemical potentials for spin-waves in ferromagnetic spin segments are introduced to ensure zero magnetization at finite temperature. This approach successfully describes the crossover from behavior of pure one-dimensional ferromagnet at high temperatures to a distinct Curie behavior due to randomness at low temperatures. We discuss the effects of impurity bond strength and concentration on the crossover and low temperature behavior.

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Xin Wan, Kun Yang, R. N. Bhatt. 2002-03-15. Modified spin-wave study of random antiferromagnetic-ferromagnetic spin chains. https://doi.org/10.1103/physrevb.66.014429

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