PACS -CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES-

http://www.aip.org/pacs/pacs08/pacs0870.html

73.43.Nq Quantum phase transitions
75.10.Pq Spin chain models
75.50.Ee Antiferromagnetics
76.30.-v Electron paramagnetic resonance and relaxation
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance

まぁ、なんとなく。