Abstract
Pr3In exhibits an antiferromagnetic transition at ~12 K. This transition appears to occur due to the exchange-generated admixture of higher lying crystal field levels into the singlet ground state. It is thus an example of an induced moment antiferromagnet. To provide detailed understanding of the magnetic behavior of Pr3In we have measured the magnetic excitation spectrum with inelastic neutron scattering experiments. As expected for an induced moment system, at temperatures comparable to the antiferromagnetic transition the effects of the magnetic exchange are so important that the crystal field excitations become propagating modes. This has the consequence that we are able to observe a clear dispersion of the crystal field excitations. However, above 100 K the dispersion of the crystal field excitations has largely vanished. This, coupled with the fact that the magnetic fluctuations no longer contribute to the bulk susceptibility, allows limits to be placed on the possible crystal field level schemes from which the induced moment transition evolves.
