The critical properties of random ferromagnets with pure specific-heat exponent ${\ensuremath{\alpha}}_{P}=0$ are analyzed using renormalization-group methods. The origin and form of the impurity-induced logarithmic corrections for the random two-dimensional Ising model are discussed. Corrections develop only for the specific heat, which presents a new singularity of the form ${|\mathrm{ln}|T\ensuremath{-}{T}_{c}||}^{1\ensuremath{-}\ensuremath{\mu}}$ as well as a new critical exponent $\ensuremath{\mu}$.The critical properties of random ferromagnets with pure specific-heat exponent ${\ensuremath{\alpha}}_{P}=0$ are analyzed using renormalization-group methods. The origin and form of the impurity-induced logarithmic corrections for the random two-dimensional Ising model are discussed. Corrections develop only for the specific heat, which presents a new singularity of the form ${|\mathrm{ln}|T\ensuremath{-}{T}_{c}||}^{1\ensuremath{-}\ensuremath{\mu}}$ as well as a new critical exponent $\ensuremath{\mu}$.

Physical review. B, Condensed matterApr 1, 198319 citations

Test of crossover scaling in the two-dimensional random-field Ising model

Kurt Binder

The random-field-induced rounding of the specific-heat singularity observed in transfer-matrix calculations of two-dimensional Ising models by Morgenstern, Binder, and Hornreich is interpreted in terms of the Fishman-Aharony scaling theory. Results qualitatively similar to recent experimental work on ${\mathrm{Rb}}_{2}$ ${\mathrm{Co}}_{0.85}$ ${\mathrm{Mg}}_{0.15}$ ${\mathrm{F}}_{4}$ are obtained.The random-field-induced rounding of the specific-heat singularity observed in transfer-matrix calculations of two-dimensional Ising models by Morgenstern, Binder, and Hornreich is interpreted in terms of the Fishman-Aharony scaling theory. Results qualitatively similar to recent experimental work on ${\mathrm{Rb}}_{2}$${\mathrm{Co}}_{0.85}$${\mathrm{Mg}}_{0.15}$${\mathrm{F}}_{4}$ are obtained.

Physical review. B, Condensed matterMay 1, 198417 citations

{\mathrm{Rb}}_{2}

{\mathrm{Co}}_{0.85}

{\mathrm{Mg}}_{0.15}

{\mathrm{F}}_{4}

are obtained.