PRESSURE-INDUCED CRITICAL-BEHAVIOR OF KMNF3 CLOSE TO P-C=3.1 GPA - X-RAY-DIFFRACTION RESULTS

Citation
S. Asbrink et A. Waskowska, PRESSURE-INDUCED CRITICAL-BEHAVIOR OF KMNF3 CLOSE TO P-C=3.1 GPA - X-RAY-DIFFRACTION RESULTS, Physical review. B, Condensed matter, 53(1), 1996, pp. 12-15
Citations number
29
Categorie Soggetti
Physics, Condensed Matter
ISSN journal
01631829
Volume
53
Issue
1
Year of publication
1996
Pages
12 - 15
Database
ISI
SICI code
0163-1829(1996)53:1<12:PCOKCT>2.0.ZU;2-9
Abstract
The critical behavior of KMnF3 close to the pressure-induced cubic-to- tetragonal structural phase transition at P-c=3.1 GPa has been studied by single-crystal x-ray diffraction. The pressure dependence of a pri mary order parameter has been determined from superlattice Bragg inten sities and was found to fulfill the power law Q=A(P-P-c)(beta). The tr ansition with a small discontinuity of the intensities close to P-c sh ows deviations from the classical behavior similarly as in the tempera ture-dependent transition at 186 K, where the domain structure conside rably affects the values of the critical parameters. However, the pres sure inhibits formation of large, single domains of definite orientati on. Instead, increased width of diffraction profiles points to the app earance of numerous, narrow domains which may influence the character of the transition.