Magnetic-Field-Induced Griffiths Phase versus Random-Field Criticality and Domain Wall Susceptibility of Fe0.47Zn0.53F2

Authors

Christian Binek, University of Nebraska-LincolnFollow
S. Kuttler, Angewandte Physik, Gerhard-Mercator-Universitat, Duisburg, Germany
Wolfgang Kleemann, Angewandte Physik, Gerhard-Mercator-Universitat, Duisburg, GermanyFollow

Date of this Version

9-18-1995

Comments

Published by American Physical Society. Copyright 1995. Permission to use. Phys. Rev. Lett. 75, 2412 (1995).

Abstract

The well-known peak of the parallel ac susceptibility arising below TN in Fe_0.47Zn_0.53F₂ splits into a narrow critical peak at T_c (H) and a broad field-induced Griffiths phase shoulder peaking at T_p>T_c(H) in magnetic fields H≳1.6 MA /m. Random-field (RF) criticality with α̃≈0 and subsequent rounding due to RF trapping of thermal fluctuations are observed upon zero-field cooling as T→T_c^-(H). The frozen domain state obtained after rapid field cooling reveals excess susceptibility Δχw′∝H^2.6, owing to rough walls with thermally activated stiffness.