Orthoferrite with a hidden lanthanide magnetic motif: NdFeO3

Abstract

Scrutiny of an established monoclinic magnetic space group for NdFeO3 reveals hitherto unknown properties of the orthoferrite. Future experiments using neutron and x-ray diffraction techniques can verify them. Neodymium ions possess Dirac multipoles, both time-odd (magnetic) and parity-odd (polar), that come with unique diffraction conditions. Non-magnetic polar Nd multipoles are permitted even though the monoclinic space group is centrosymmetric. Dirac multipoles are forbidden by symmetry at sites occupied by ferric ions. Available diffraction patterns have not been analysed for Dirac multipoles. Nor all permitted components of the axial dipoles and quadrupoles. In the case of neutron diffraction, magnetic quadrupoles are correlations between anapole and orbital degrees of freedom. We give conditions for the observation of Templeton-Templeton scattering of x-rays, created by angular anisotropy in the electronic charge distribution. Axial multipoles are the sole providers of dichroic signals.

References in corpus (11)

• The macroscopic monopolization in diagonal magnetoelectrics
• Theory of neutron scattering by electrons in magnetic materials
• Magnetoelectric multipoles in metals
• Experimental evidence of anapolar moments in the antiferromagnetic insulating phase of V2O3 obtained from x-ray resonant Bragg diffraction
• Direct observation of anapoles by neutron diffraction
• Ordered state of magnetic charge in the pseudo-gap phase of a cuprate superconductor (HgBa2CuO4)
• Spin Jahn-Teller antiferromagnetism in CoTi${}_2$O${}_5$
• Anapole Correlations in Sr2IrO4 Defy the jeff = 1/2 Model
• Electronic multipoles in second harmonic generation and neutron scattering
• Spin dynamics and exchange interaction in orthoferrite TbFeO${}_3$ with non-Kramers rare-earth ion
• Polar magnetization unveiled by polarized neutron diffraction