First Order Transitions and Multicritical Points in Weak Itinerant Ferromagnets

D. Belitz; T. R. Kirkpatrick; Thomas Vojta

doi:10.1103/PhysRevLett.82.4707

First Order Transitions and Multicritical Points in Weak Itinerant Ferromagnets

D. Belitz, T. R. Kirkpatrick, and Thomas Vojta

Phys. Rev. Lett. 82, 4707 – Published 7 June 1999

Abstract

It is shown that the phase transition in low- $T_{c}$ clean itinerant ferromagnets is generically of first order, due to correlation effects that lead to a nonanalytic term in the free energy. A tricritical point separates the line of first order transitions from Heisenberg critical behavior at higher temperatures. Sufficiently strong quenched disorder suppresses the first order transition via the appearance of a critical end point. A semiquantitative discussion is given in terms of recent experiments on MnSi, and predictions for other experiments are made.

Received 4 January 1999

DOI:https://doi.org/10.1103/PhysRevLett.82.4707

Authors & Affiliations

D. Belitz^* and T. R. Kirkpatrick^†

Institute for Theoretical Physics, University of California, Santa Barbara, California 93106

Thomas Vojta

Institut für Physik, TU Chemnitz, D-09107 Chemnitz, Germany

^*Permanent address: Department of Physics, and Materials Science Institute, University of Oregon, Eugene, OR 97403.
^†Permanent address: Institute for Physical Science and Technology, and Department of Physics, University of Maryland, College Park, MD 20742.