The negative values of J1and J2 indicate the existence of antiferromagnetic
coupling between Mn(II) ions.
Our open-end coaxial probe measurements at the end of the paper attempt to observe the weak ferromagnetic resonance due to spin canting seen particularly in antiferromagnetic
resonance investigations on crystalline [alpha]-[Fe.sub.2][O.sub.3], also known as the mineral hematite (6), (8).
Observed Mn-O distances at 2 K compared against the expected distortions for each of the three low temperature magnetic perovskite phases in ([Pr.sub.0.35][Y.sub.0.07][Th.sub.0.04][Ca.sub.0.04] [Sr.sub.0.5])Mn[O.sub.3] Observed Mn-O Phase Expected Mn[O.sub.6] distances (and properties) octahedral geometry ([Angstrom]) F type Regular 1.936(1) X 4 (ferromagnetic, metallic) 1.936(1) X 2 A type Tetragonal compression 1.901(1) X 2 (antiferromagnetic
, 1.948(1) X 4 2-dimensional conductor) CE type [Mn.sup.3+] site (a): 1.900(3) X 2 (charge ordered, tetragonal elongation 1.925(5) X 2 antiferromagnetic
2.056(6) X 2 insulator) [Mn.sup.4+] site (a): 1.907(1) X 2 regular 1.916(1) X 2 1.919(1) X 2 (a) The refinement was constrained to preserve the centres of symmetry of these octahedra.
However, there are other examples, like iron trithiohypophosphate (FePS3), which remarkably keeps its antiferromagnetic
ordering intact all the way down to monolayer.
There is a spin cyclical order with a period of 64 nm which is superimposed on this antiferromagnetic
A wide application of materials containing nanosized antiferromagnetic
particles in different branches of nanotechnology is primarily due to a number of specific structural, magnetic, and thermodynamic properties of these materials found within long-term fundamental studies.
However, one limitation to the synthesis of metal nanoparticles is their reactivity toward air environment, which may degrade their ferromagnetic character by forming an antiferromagnetic
Carpenter, "Co[F.sub.2]: A model system for magnetoelastic coupling and elastic softening mechanisms associated with paramagnetic [left and right arrow] antiferromagnetic
phase transitions," Journal of Physics: Condensed Matter, vol.
They are classified as ferrimagnetics with both ferromagnetic (FM) and antiferromagnetic
(AF) coupling between atomic moments, and the magnetic coupling depends on the specific crystallographic position of Fe ions .
In the case of HTSC, it has been demonstrated that the antiferromagnetic
(AF) and superconducting (SC) phases d-wave [1-4] and p-wave  superconductors can be given a unified explanation in terms of a nonlinear sigma model for a field which behaves as a vector transformation under SO(5) rotations.