Frustration effects in antiferromagnetic molecules: The cuboctahedron

Frustration of magnetic systems which is caused by competing interactions is the driving force of several unusual phenomena such as plateaus and jumps of the magnetization curve as well as of unusual energy spectra with for instance many singlet levels below the first triplet state. The antiferromagnetic cuboctahedron can serve as a paradigmatic example of certain frustrated antiferromagnets. In addition it has the advantage that its complete energy spectrum can be obtained up to individual spin quantum numbers of s = 3/2 (16 777 216 states).

Frustration of magnetic systems which is caused by competing interactions is the driving force of several unusual phenomena such as plateaus and jumps of the magnetization curve as well as of unusual energy spectra with for instance many singlet levels below the first triplet state. The antiferromagnetic cuboctahedron can serve as a paradigmatic example of certain frustrated antiferromagnets. The graphics displays the heat capacity for the regular cuboctahedron with s = 1/2, s = 1, and s = 3/2. The low-lying singlets lead to a prominent sharp peak at low temperatures especially in the case of s = 1/2.Figure optionsDownload as PowerPoint slide