Orphan spins and bound in-gap states in the $S=\frac{5}{2}$ antiferromagnet CaFe${}_2$O${}_4$

Abstract

CaFe${}_2$O${}_4$ is an anisotropic $S=\frac{5}{2}$ antiferromagnet with two competing $A$ ($\uparrow \uparrow \downarrow \downarrow$) and $B$ ($\uparrow \downarrow \uparrow \downarrow$) magnetic order parameters separated by static antiphase boundaries at low temperatures. Neutron diffraction and bulk susceptibility measurements, show that the spins near these boundaries are weakly correlated and a carry an uncompensated ferromagnetic moment that can be tuned with a magnetic field. Spectroscopic measurements find these spins are bound with excitation energies less than the bulk magnetic spin-waves and resemble the spectra from isolated spin-clusters. Localized bound orphaned spins separate the two competing magnetic order parameters in CaFe${}_2$O${}_4$.

arXiv comment(main text - 5 pages, 4 figures; supplementary information - 4 pages, 6 figures, to be published in Physical Review Letters). arXiv admin note: text overlap with arXiv:1606.04243

References in corpus (22)

• Topological Insulators
• Antiferromagnetic spintronics
• Topological Magnon Insulator in Insulating Ferromagnet
• STM Studies of the Electronic Structure of Vortex Cores in Bi2Sr2CaCu2O8+d
• Staggering antiferromagnetic domain wall velocity in a staggered spin-orbit field
• Antiferromagnetic domain wall motion driven by spin-orbit torques
• Low-lying Quasiparticle Excitations around a Vortex Core in Quantum Limit
• Magnetic Cluster Excitations
• Magnetic susceptibility of diluted pyrochlore and SCGO antiferromagnets
• Emergent honeycomb lattice in LiZn2Mo3O8
• Incommensurate short-range order in the S=1 triangular antiferromagnet NiGa2S4
• Structure of end states for a Haldane Spin Chain
• Mesoscopic Phase Coherence in a Quantum Spin Fluid
• A fractionalised "${\mathbb{Z}}_2$" classical Heisenberg spin liquid
• Solitary magnons in the $S=\frac{5}{2}$ antiferromagnet CaFe${}_2$O${}_4$
• Effects of Disorder on the Competition between Antiferromagnetism and Superconductivity
• Spin Fluctuations from Hertz to Terahertz on a Triangular Lattice
• Emergent interacting spin islands in a depleted strong-leg Heisenberg ladder
• Domain Wall Spin Dynamics in Kagome Antiferromagnets
• Dopant-Bound Spinons in Cu_(1-x)Zn_xGeO_3
• Magnetic field resonantly enhanced free spins in underdoped YBa${}_2$Cu${}_3$O${}_{6+x}$
• Fluctuating defects in the incipient relaxor K${}_{1-x}$Li${}_x$TaO${}_3$ (x=0.02)

Cited by in corpus (7)

• Interconversion of multiferroic domains and domain walls
• Structure and magnetic properties of epitaxial CaFe2O4 thin films
• Metastable antiphase boundary ordering in CaFe${}_2$O${}_4$
• From one- to two-magnon excitations in the S=3/2 magnet $\beta$-CaCr${}_2$O${}_4$
• Non-linear soliton confinement in weakly coupled antiferromagnetic spin chains
• Metastable and localized Ising magnetism in $\alpha$-CoV${}_2$O${}_6$ magnetization plateaus
• Unusual ferrimagnetism in CaFe2O4