Effects of random fields on bicritical phase diagrams in two and three dimensions

✍ Scribed by R.J. Birgeneau; A. Aharony; R.A. Cowley; J.P. Hill; R.A. Pelcovits; G. Shirane; T.R. Thurston

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 451 KB
• Volume: 177
• Category: Article
• ISSN: 0378-4371
• DOI: 10.1016/0378-4371(91)90134-x

✦ Synopsis

Stimulated by the pioneering work of Michael Fisher and collaborators on bicritical phase diagrams in pure systems, we consider the corresponding behavior in systems with uniaxial random fields. We discuss experiments in the two-and three-dimensional n= 3 systems Rb2Mno vMgo 3F4 and Mno 75Zno.25F2, respectively. We also report a new theory for the 2D n = 3 system, which predicts a novel phase boundary geometry. In both two and three dimensions the lsing component is dominated by metastability effects. However, the ,¥Y component shows a reversible transition to long range order. Experiments in the bicritical region in Mn07sZno 2sF2 are inconclusive. However, the theory describes the measured XY phase boundary in Rb2Mno 7Mgo 3F4 quite well.