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Crossover from classical to random-field critical exponents in As-doped TbVO4

C. H. Choo·H. P. Schriemer·D. R. Taylor
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Abstract

Using birefringence techniques we have measured the critical exponents beta, gamma, and delta in As-doped TbVO4, a structural realization of the random-field Ising model where random strain fields are introduced by V-As size mismatch. For pure TbVO4 we observe the expected classical critical exponents, while for a mixed sample with 15% As concentration our results are beta=0.31 +/-0.03, gamma=1.22 +/-0.07, and delta=4.2 +/-0.7. These values are consistent with the critical exponents for the short range pure Ising model in three dimensions in agreement with a prediction by Toh. The susceptibility data showed a crossover with temperature from classical to random field critical behaviour.

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C. H. Choo, H. P. Schriemer, D. R. Taylor. 2000-02-10. Crossover from classical to random-field critical exponents in As-doped TbVO4. https://doi.org/10.1103/physrevb.61.11197

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