MAGNETIC DIPOLE-DIPOLE INTERACTIONS AND SINGLE-ION-ANISOTROPY - REVISITING A CLASSICAL APPROACH TO MAGNETS

The weak classical through-space magnetic dipolar interactions have, i n general, not been an important component in stabilizing bulk magnets , as the strong quantum-mechanical through-bond exchange couplings dom inate. We show that for materials composed of strongly exchange-couple d magnetic chains with very weak interchain exchange, the interchain d ipolar interactions may dominate, leading to sizable ordering temperat ures. The single-ion anisotropy together with the anisotropy of the di pole interaction determine the magnetic ordering directions. The famil y of [Mn(porphyrin)](+)[cyanocarbon](-) magnets is shown to order due to classical interchain dipolar interaction in combination with the si ngle-ion anisotropy, resulting in canted magnetic structures.