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

Article

关键词: ISING-MODEL;    PHASE-TRANSITIONS;    CRITICAL-BEHAVIOR;    FE0.93ZN0.07F2;    BIREFRINGENCE;    SCATTERING;   

DOI  :  10.1103/PhysRevB.61.11197

来源: SCIE

【 摘 要 】

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 behavior.

【 授权许可】

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