Magnetism: Magnetic ions in insulators, their interactions, resonances, and optical properties

anisotropy energy antiferromagnetic applied approximation arising assumed atoms axes axis calculation compared components consider constant contribution correct corresponding coupling crystal crystal field cubic dependence detailed determined dipolar direction discussed effect electron elements equations estimate example exchange exchange interaction excited expected experiment experimental expression external fact ferromagnetic field frequency give given ground important induced integral interaction iron latter lattice ligand linear magnetic field magnitude materials measurements mechanism metals molecular field neighbors observed obtained operators orbital orientation origin pairs parallel paramagnetic perturbation Phys plane positive possible present problem reference relation resonance respectively result shown similar single spin Hamiltonian spin wave splitting structure studies sublattice substances superexchange symmetry temperature theoretical theory tion transition usually values various wave function weak zero