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Quantum critical behavior of itinerant ferromagnets
Author(s) -
Vojta Thomas,
Belitz D.,
Kirkpatrick T.R.,
Narayanan R.
Publication year - 1999
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/(sici)1521-3889(199911)8:7/9<593::aid-andp593>3.0.co;2-f
Subject(s) - ferromagnetism , condensed matter physics , quantum phase transition , antiferromagnetism , physics , phase diagram , quantum critical point , multicritical point , phase transition , gravitational singularity , quantum fluctuation , quantum , quantum phases , phase (matter) , quantum mechanics
We investigate the quantum phase transition of itinerant ferromagnets. It is shown that correlation effects in the underlying itinerant electron system lead to singularities in the order parameter field theory that result in an effective long‐range interaction between the spin fluctuations. This interaction turns out to be generically antiferromagnetic for clean systems. In disordered systems analogous correlation effects lead to even stronger singularities. The resulting long‐range interaction is, however, generically ferromagnetic. We discuss two possibilities for the ferromagnetic quantum phase transition. In clean systems, the transition is generically of first order, as is experimentally observed in MnSi. However, under certain conditions the transition may be continuous with non‐mean field critical behavior. In disordered systems, one finds a very rich phase diagram showing first order and continuous phase transitions and several multicritical points.