Physics – Condensed Matter – Strongly Correlated Electrons
Scientific paper
2008-01-17
J. Phys.:Condens. Matter 20 (2008) 325219
Physics
Condensed Matter
Strongly Correlated Electrons
9 pages, 8 figures
Scientific paper
10.1088/0953-8984/20/32/325219
Two-sublattice ferrimagnet, with spin-$s_1$ operators $\bf{S_{1i}}$ at the sublattice $A$ site and spin-$s_2$ operators $\bf{S_{2i}}$ at the sublattice $B$ site, is considered. The magnon of the system, the transversal fluctuation of the total magnetization, is a complicate mixture of the transversal fluctuations of the sublattice $A$ and $B$ spins. As a result, the magnons' fluctuations suppress in a different way the magnetic orders of the $A$ and $B$ sublattices and one obtains two phases. At low temperature $(0,T^*)$ the magnetic orders of the $A$ and $B$ spins contribute to the magnetization of the system, while at the high temperature $(T^*,T_N)$, the magnetic order of the spins with a weaker intra-sublattice exchange is suppressed by magnon fluctuations, and only the spins with stronger intra-sublattice exchange has non-zero spontaneous magnetization. The $T^*$ transition is a transition between two spin-ordered phases in contrast to the transition from spin-ordered state to disordered state ($T_N$-transition). There is no additional symmetry breaking, and the Goldstone boson has a ferromagnetic dispersion in both phases. A modified spin-wave theory is developed to describe the two phases. All known Neel's anomalous $M(T)$ curves are reproduced, in particular that with "compensation point". The theoretical curves are compared with experimental ones for sulpho-spinel $MnCr2S_{4-x}Se_{x}$ and rare earth iron garnets.
No associations
LandOfFree
Towards the theory of ferrimagnetism does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Towards the theory of ferrimagnetism, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Towards the theory of ferrimagnetism will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-392999