title: Colossal magnetoresistance in manganites as a multicritical phenomenon.
abstract: The colossal magnetoresistance in manganites AMnO3 is studied from the viewpoint of multicritical phenomena. To understand the complicated interplay of various phases, we study the Ginzburg-Landau theory in terms of both the mean-field approximation and the renormalization-group analysis for comparison with the observed phase diagram. Several novel features, such as the first-order ferromagnetic transition and the dip in the transition temperature near the multicritical point, can be understood as being driven by enhanced fluctuations near the multicritical point. Furthermore, we obtain a universal scaling relation for the H/M versus M2 plot (Arrott plot), which fits rather well with the experimental data, providing further evidence for the enhanced fluctuation.
authors.affiliation: Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Murakami
authors.forename: Naoto
authors.initials: N
authors.lastname: Nagaosa