Τίτλος:
Phase diagram and critical behavior of the random ferromagnet Ga1 -xMnxN
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
Molecular beam epitaxy has been employed to obtain Ga1-xMn xN films with x up to 10% and Curie temperatures TC up to 13 K. The magnitudes of TC and their dependence on x, T C(x)xm, where m=2.2±0.2, are quantitatively described by a tight-binding model of superexchange interactions and Monte Carlo simulations of TC. The critical behavior of this dilute magnetic insulator shows strong deviations from the magnetically clean case (x=1), in particular, (i) an apparent breakdown of the Harris criterion, (ii) a nonmonotonic crossover in the values of the susceptibility critical exponent γeff between the high temperature and critical regimes, and (iii) a smearing of the critical region, which can be explained either by the Griffiths effects or by macroscopic inhomogeneities in the spin distribution with a variance Δx=(0. 2±0.1)%. © 2013 American Physical Society.
Συγγραφείς:
Stefanowicz, S.
Kunert, G.
Simserides, C.
Majewski, J.A.
Stefanowicz, W.
Kruse, C.
Figge, S.
Li, T.
Jakieła, R.
Trohidou, K.N.
Bonanni, A.
Hommel, D.
Sawicki, M.
Dietl, T.
Περιοδικό:
PHYSICAL REVIEW B : CONDENSED MATTER AND MATERIALS PHYSICS
DOI:
10.1103/PhysRevB.88.081201
