Summary: High­Temperature Series Analysis of 2D Random­Bond Ising Ferromagnets Confirms
the Shalaev, Shankar and Ludwig Exponents
Alexandra Roder 1 , Joan Adler 2 and Wolfhard Janke 1
1 Institut f¨ur Physik, Johannes Gutenberg­Universit¨at Mainz, Staudinger Weg 7, 55099 Mainz, Germany.
2 Department of Physics, Technion, Haifa 32000, Israel.
(February 23, 1998)
We analyse new high­temperature series expansions for the
susceptibility, Ø, of the two­dimensional random­bond Ising
ferromagnet with a symmetric bimodal distribution of two
positive couplings J1 and J2 . By studying a wide range of
coupling ratios J2=J1 we obtain compelling evidence for a
critical behavior of the form Ø ¸ t \Gamma7=4 j ln tj 7=8 , as predicted
theoretically by Shalaev, Shankar, and Ludwig.
The study of critical phenomena in real materials is
often complicated by the influence of impurities and in­
homogeneities. Since this is the typical situation in most
experiments, it is of great importance to develop a theor­
etical understanding of the role of these non­ideal effects.
One important question is whether the critical properties
of the considered system are robust against such random

Source: Adler, Joan - Physics Department, Technion, Israel Institute of Technology

Collections: Physics