Spin order and fluctuations in the EuAl${}_4$ and EuGa${}_4$ topological antiferromagnets: A $\mu$SR study

Abstract

We report on systematic muon-spin rotation and relaxation ($\mu$SR) studies of the magnetic properties of EuAl${}_4$ and EuGa${}_4$ single crystals at a microscopic level. Transverse-field $\mu$SR measurements, spanning a wide temperature range (from 1.5 to 50 K), show clear bulk AFM transitions, with an almost 100% magnetic volume fraction in both cases. Zero-field $\mu$SR measurements, covering both the AFM and the paramagnetic (PM) states, reveal internal magnetic fields $B_{\mathrm{int}}(0)=0.33$ T and 0.89 T in EuAl${}_4$ and EuGa${}_4$, respectively. The transverse muon-spin relaxation rate ${\lambda }_{\mathrm{T}}$, a measure of the internal field distribution at the muon-stopping site, shows a contrasting behavior. In EuGa${}_4$, it decreases with lowering the temperature, reaching its minimum at zero temperature, ${\lambda }_{\mathrm{T}}(0)=0.71$ $\mu$s${}^{-1}$. In EuAl${}_4$, it increases significantly below $T_{\mathrm{N}}$, to reach 58 $\mu$s${}^{-1}$ at 1.5 K, most likely reflecting the complex magnetic structure and the competing interactions in the AFM state of EuAl${}_4$. In both compounds, the temperature-dependent longitudinal muon-spin relaxation ${\lambda }_{\mathrm{L}}(T)$, an indication of the rate of spin fluctuations, diverges near the onset of AFM order, followed by a significant drop at $T<T_{\mathrm{N}}$. In the AFM state, spin fluctuations are much stronger in EuAl${}_4$ than in EuGa${}_4$, while being comparable in the PM state. The evidence of robust spin fluctuations against the external magnetic fields provided by $\mu$SR may offer new insights into the origin of the topological Hall effect and the possible magnetic skyrmions in the EuAl${}_4$ and EuGa${}_4$ compounds.

arXiv comment10 pages, 7 figures, accepted by Phys. Rev. B

References in corpus (29)

• Skyrmion Lattice in a Chiral Magnet
• Weyl and Dirac Semimetals in Three Dimensional Solids
• Advances in the Physics of Magnetic Skyrmions and Perspective for Technology
• Topological Hall effect in the A-phase of MnSi
• Spin Transfer Torques in MnSi at Ultra-low Current Densities
• Emergent electrodynamics of skyrmions in a chiral magnet
• Skyrmion lattice with a giant topological Hall effect in a frustrated triangular-lattice magnet
• A new class of chiral materials hosting magnetic skyrmions beyond room temperature
• musrfit: A free platform-independent framework for muSR data analysis
• Interface-driven topological Hall effect in SrRuO${}_3$-SrIrO${}_3$ bilayer
• Unusual Hall Effect Anomaly in MnSi Under Pressure
• Skyrmion phase and competing magnetic orders on a breathing kagome lattice
• Nanometric square skyrmion lattice in a centrosymmetric tetragonal magnet
• Robust formation of skyrmions and topological Hall effect in epitaxial thin films of MnSi
• Formation and rotation of skyrmion crystal in the chiral-lattice insulator Cu2OSeO3
• Spin fluctuation induced Weyl semimetal state in the paramagnetic phase of EuCd${}_2$As${}_2$
• Real-Space and Reciprocal-Space Berry Phases in the Hall Effect of Mn${}_{1-\mathrm{x}}$Fe${}_{\mathrm{x}}$Si
• Dzyaloshinskii-Moriya interaction and Hall effects in the skyrmion phase of MnFeGe alloys
• Anomalous Hall resistivity and possible topological Hall effect in the EuAl${}_4$ antiferromagnet
• Large topological Hall effect in a geometrically frustrated kagome magnet Fe${}_3$Sn${}_2$
• Unconventional transverse transport above and below the magnetic transition temperature in Weyl semimetal EuCd${}_2$As${}_2$
• Charge-Density-Wave Order and Multiple Magnetic Transitions in Divalent Europium Compound EuAl${}_4$
• Magnetic phases of skyrmion-hosting GaV${}_4$S${}_{8-y}$Se${}_y$ ($y=0,2,4,8$) probed with muon spectroscopy
• Giant magnetoresistance and topological Hall effect in the EuGa4 antiferromagnet
• Magnetic structure of divalent europium compound EuGa${}_4$ studied by single crystal time-of-flight neutron diffraction
• Megahertz dynamics in skyrmion systems probed with muon-spin relaxation
• Muon-spin rotation and magnetization studies of chemical and hydrostatic pressure effects in EuFe_{2}(As_{1-x}P_{x})_{2}
• Magnetic phase diagram of Ca-substituted EuFe${}_2$As${}_2$
• Magnetism behavior of $T^{\prime }$-type Eu${}_2$CuO${}_4$ revealed by muon spin rotation/relaxation measurements

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• Ab initio exploration of short-pitch skyrmion materials: Role of orbital frustration
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