Dzyaloshinskii interaction and exchange-relativistic effects in orthoferrites

Abstract

We present an overview of the microscopic theory of the Dzyaloshinskii-Moriya (DM) coupling and related exchange-relativistic effects such as exchange anisotropy, electron-nuclear antisymmetric supertransferred hyperfine interactions, antisymmetric magnetogyrotropic effects, and antisymmetric magnetoelectric coupling in strongly correlated 3$d$ compounds focusing on orthoferrites RFeO${}_3$ (R is a rare-earth ion or yttrium Y). % Particular emphasis will be placed on the role of crystal field effects, the sense and direction of the Dzyaloshinskii vector, its dependence on the superexchange bonding geometry, and other subtle features of exchange-relativistic effects. Most attention in the paper centers around the derivation of the Dzyaloshinskii vector, its value, orientation, and sense (sign) under different types of the (super)exchange interaction and crystal field. Microscopically derived expression for the dependence of the Dzyaloshinskii vector on the superexchange geometry allows one to find all the overt and hidden canting angles in orthoferrites RFeO${}_3$ as well as corresponding contribution to magnetic anisotropy. Being based on the theoretical predictions regarding the sign of the Dzyaloshinskii vector we have predicted and study in detail a novel magnetic phenomenon, {\it weak ferrimagnetism} in mixed weak ferromagnets with competing signs of the Dzyaloshinskii vectors. The ligand NMR measurements in weak ferromagnets are shown to be an effective tool to inspect the effects of DM coupling in an external magnetic field. Along with orthoferrites RFeO${}_3$ and weak ferrimagnets RFe${}_{1-x}$Cr${}_x$O${}_3$, although to a lesser extent, we address such typical weak ferromagnets as $\alpha$-Fe${}_2$O${}_3$, FeBO${}_3$, and FeF${}_3$.

41 pages, 12 figures

References in corpus (10)

• Spin current and magneto-electric effect in non-collinear magnets
• Spontaneous Skyrmion Ground States in Magnetic Metals
• Role of the Dzyaloshinskii-Moriya interaction in multiferroic perovskites
• Magnetically driven ferroelectric order in Ni${}_3$V${}_2$O${}_8$
• Twisted magnetic patterns: Exploring the Dzyaloshinskii--Moriya vector
• Microscopic mechanisms of spin-dependent electric polarization in 3d oxides
• Nonrelativistic Multiferroicity in the Nonstoichiometric Spin s=1/2 Spiral Chain Cuprate LiCu2O2
• Multiferroicity due to nonstoichiometry in the chain cuprate LiVCuO_4
• Dzyaloshinsky-Moriya antisymmetric exchange coupling in cuprates: Oxygen effects
• Quantum effects in muon spin spectroscopy within the stochastic self-consistent harmonic approximation

Cited by in corpus (9)

• Anisotropic long-range spin transport in canted antiferromagnetic orthoferrite YFeO${}_3$
• Structure-property relationships for weak-ferromagnetic perovskites
• Surface-symmetry-driven Dzyaloshinskii--Moriya interaction and canted ferrimagnetism in collinear magnetoelectric antiferromagnet Cr${}_2$O${}_3$
• Lattice dynamics and mixing of polar phonons in the rare-earth orthoferrite TbFeO${}_3$
• Charge transfer transitions and circular magnetooptics in ferrites
• Simple Realistic Model of Spin Reorientation in 4f-3d Compounds
• Dzyaloshinskii-Moriya spin density by skew scattering
• Insulator-bad metal transition in RNiO${}_3$ nickelates beyond Hubbard model and density functional theory
• Magnetostructural Coupling at the Néel point in YNiO3 Single Crystals