Frustration in a transverse Ising nanoisland with an antiferromagnetic spin configuration

The phase diagrams, saturation magnetizations and temperature dependences of magnetizations in a transverse Ising nanoisland with an antiferromagnetic spin configuration are studied by the uses of the effective-field theory with correlations (EFT) and the mean-field approximation (MFA), in order to clarify whether the MFA can be successfully applied to the theoretical discussions of naonoislands. From these investigations, we have found a lot of unexpected characteristic phenomena in these properties, when the value of an interlayer coupling takes a large value. We have also found that the applications of the MFA to the magnetic properties are extremely restricted for nanoislands, when the value of an interlayer coupling takes a large value, in contrast to a number of bulk studies.