Magnetic dipole splitting of magnon bands in a two dimensional antiferromagnet

•The paper shows that the source of magnetic anisotropy in MnPS3 is largely magnetic dipole.•The technique of neutron resonance spin echo spectroscopy is capable of resolving the energies of magnetic excitations down to micro electron volts. Neutron resonant spin echo spectroscopy has been applied to measure the splitting of the magnon bands due to the magnetic dipole interaction in the two dimensional antiferromagnet MnPS3. The splittings measured are more than two orders of magnitude smaller than energies of the magnons. Simulation of the magnon energies involving the calculation of the magnetic dipole interaction in MnPS3 predict splittings a little higher than those measured. The comparison confirms that the magnetic dipole interaction provides most of the anisotropy which stabilises the antiferromagnetic order in MnPS3. We present the first evidence for the splitting of magnon bands due to the magnetic dipole interaction in a two dimensional antiferromagnet.