TY - JOUR
TI - Phase diagram and critical behavior of the random ferromagnet Ga1 -xMnxN
AU - Stefanowicz, S.
AU - Kunert, G.
AU - Simserides, C.
AU - Majewski, J.A.
AU - Stefanowicz, W.
AU - Kruse, C.
AU - Figge, S.
AU - Li, T.
AU - Jakieła, R.
AU - Trohidou, K.N.
AU - Bonanni, A.
AU - Hommel, D.
AU - Sawicki, M.
AU - Dietl, T.
JO - PHYSICAL REVIEW B : CONDENSED MATTER AND MATERIALS PHYSICS
PY - 2013
VL - 88
TODO - 8
SP - null
PB - 
SN - 1098-0121
TODO - 10.1103/PhysRevB.88.081201
TODO - null
TODO - 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.
ER -