The spin dynamics of the layered square-lattice vanadate Pb${}_{2}$VO(PO${}_{4}$)${}_{2}$ is investigated by electron resonance (ESR) at various magnetic fields and temperatures above ordering. linewidth divergence towards low seems to agree with isotropic Heisenberg-type exchange suggesting that relaxation in this quasi-two-dimensional compound governed low-dimensional quantum fluctuations. However, a weak easy-plane anisotropy $g$ factor points presence planar XY type exchange. Indeed, we...

We report a structural-magnetic investigation by x-ray absorption spectroscopy (XAS), neutron diffraction, dc susceptibility $({\ensuremath{\chi}}_{\text{dc}})$, and electron spin resonance (ESR) of the 12R-type perovskite ${\text{BaTi}}_{1/2}{\text{Mn}}_{1/2}{\text{O}}_{3}$. Our structural analysis diffraction supports existence trimers with chemically disordered occupancy ${\text{Mn}}^{4+}$ ${\text{Ti}}^{4+}$ ions, valence Mn ions confirmed XAS measurements. The magnetic properties are...

Luminescent layered double hydroxides (LDH) intercalated by isophthalate (ISO) and nitrilotriacetate (NTA) have been synthesized characterized powder X-ray diffraction (PXRD), extended absorption fine structure (EXAFS), elemental analysis (ICP-OES CHN), photoluminescence spectroscopy. While PXRD shows the successful formation of ZnAlEu LDHs, EXAFS reveals that Eu activators are hosted in hydroxide layers with an eightfold, oxygen-rich coordination, distinct from sixfold coordination expected...

It is currently understood that high temperature superconductivity (SC) in the transition metal $(M)$ substituted iron arsenides $\mathrm{Ba}{({\mathrm{Fe}}_{1\ensuremath{-}x}{M}_{x})}_{2}{\mathrm{As}}_{2}$ promoted by magnetic excitations with wave vectors $(\ensuremath{\pi},0)$ or $(0,\ensuremath{\pi})$. known while a small amount of Co substitution lead to SC, same does not occur for Mn any value $x$. In this work,...

Magnetic frustration and disorder are key ingredients to prevent the onset of magnetic order. In disordered hexagonal double perovskite ${\mathrm{BaTi}}_{1/2}{\mathrm{Mn}}_{1/2}{\mathrm{O}}_{3}$, ${\mathrm{Mn}}^{4+}$ cations, with $S=3/2$ spins, can either form highly correlated states trimers or dimers remain as weakly interacting orphan spins. At low temperature ($T$), dimer response is negligible, magnetism dominated by orphans. To explore role frustration, possibly quantum fluctuations,...

The polarization dependence of the near edge x-ray absorption spectroscopy (XANES) is an element specific probe to real-space distribution density unoccupied states in solid-state materials. In this paper, we present Fe and As $K$-edge experiments $\mathrm{Ba}{({\mathrm{Fe}}_{1\ensuremath{-}x}{M}_{x})}_{2}{\mathrm{As}}_{2}$ ($M=\mathrm{Mn}$, Co, $x=0.0$ 0.08). reveal a strong probed XANES spectra, which concerns mainly increase intensity electronic transitions when beam set out sample's $ab$...

The photoluminescence properties (PL) of Eu3+ hosted in the hydroxide layers layered double hydroxides (LDHs) enables calibrationless quantification anions interlayers. concept is demonstrated during nitrate-to-carbonate ion exchange Zn2+/Al3+/Eu3+ LDHs and can be implemented as a remote optical sensor to detect intrusion such Cl- or CO32-.

Electron-spin-resonance (ESR) measurements performed on the filled skutterudite system ${\text{Ce}}_{1\ensuremath{-}x}{\text{Yb}}_{x}{\text{Fe}}_{4}{\text{P}}_{12}$ $(x\ensuremath{\lesssim}0.003)$ unequivocally reveal coexistence of two ${\text{Yb}}^{3+}$ resonances associated with sites considerably different occupations and temperature behaviors. Detailed analysis ESR data suggests a scenario where fraction oversized ${({\text{Fe}}_{2}{\text{P}}_{3})}_{4}$ cages that host Yb ions are low...

The layered compound EuFe2As2 is an interesting model system to investigate the effects of well-defined local Eu2+ 4f states on itinerant electronic and magnetic properties FeAs layers. To address this subject, we investigated series EuFe2−xCoxAs2 (0.1 ⩽ x 0.75) by electron spin resonance (ESR) probe dynamics subsystem. We relate results dc-susceptibility measurements band structure calculations. As a consequence weak coupling between subsystems, found that relaxation well understood in...

Incorporation of Eu 3+ in the hydroxide layers layered double hydroxides (LDH) enables curvature LDH sheets, allowing self-assembly high surface area nanotubes through a facile soft-templating strategy.

Recent experiments on $\mathrm{G}{\mathrm{d}}^{3+}$ electron-spin resonance (ESR) in the filled skutterudite $\mathrm{C}{\mathrm{e}}_{1\ensuremath{-}x}\mathrm{G}{\mathrm{d}}_{x}\mathrm{F}{\mathrm{e}}_{4}{\mathrm{P}}_{12}(x\ensuremath{\approx}0.001)$, at temperatures where host resistivity manifests a smooth insulator-metal crossover, provide evidence of underlying Kondo physics associated with this system. At low (below $T\ensuremath{\approx}160$ K),...

Despite extensive research on the skutterudites for last decade, their electric crystalline field ground state is still a matter of controversy. We show that electron spin resonance (ESR) measurements can determine full set crystal parameters (CFPs) ${T}_{h}$ cubic symmetry $(Im3)$ ${\text{Ce}}_{1\ensuremath{-}x}{R}_{x}{\text{Fe}}_{4}{\text{P}}_{12}$ ($R=\text{Dy}$, Er, Yb; $x\ensuremath{\lesssim}0.003$) skutterudite compounds. From analysis ESR data three CFPs ${B}_{4}^{c}$, ${B}_{6}^{c}$,...

Chemical substitution is commonly used to explore new ground states in materials, yet the role of disorder often overlooked. In Mn-substituted ${\mathrm{BaFe}}_{2}{\mathrm{As}}_{2}$ (MnBFA), superconductivity (SC) absent, despite being observed for nominal hole-doped phases. Instead, a glassy magnetic phase emerges, associated with $S=5/2$ Mn local spins. this work, we present comprehensive investigation electronic structure MnBFA using angle-resolved photoemission spectroscopy (ARPES). We...

We report electron spin resonance (ESR) measurements in the Gd${}^{3+}$ doped semiconducting filled skutterudite compound Ce${}_{1\text{\ensuremath{-}}x}$Gd${}_{x}$Fe${}_{4}$P${}_{12}$ ($x\ensuremath{\approx}0.001$). As temperature $T$ varies from $T\ensuremath{\simeq}$ 150 K to 165 K, ESR fine and hyperfine structures coalesce into a broad inhomogeneous single resonance. At 200 line narrows as increases further, becomes homogeneous with thermal broadening of 1.1(2) Oe/K. These results...

Vibrational and elastic properties of the $R$Fe$_{4}$Sb$_{12}$ skutterudites are investigated by, respectively, temperature $(T)$ dependent extended X-ray absorption fine structure (EXAFS) pressure $(P)$ x-ray diffraction (XRD) experiments. The Fe $K$-edge EXAFS experiments $R=$ K, Ca Ba materials were performed in $T$-interval $6<T<300$ K XRD Na, Ca, Sr $P$-interval $1\text{ atm }<P<16$ GPa. From EXAFS, we obtained correlated Debye-Waller parameters that thus analyzed to extract effective...

A detailed study of the spin dynamics S-state ions Gd3+ and Eu2+ in filled skutterudites La1-xRxPt4Ge12 (R= Gd, Eu) is reported. The investigated directly by means electron resonance (ESR), performed at X-band (~ 9.4 GHz) Q-band 34 frequencies temperature intervals 8<T<300 K 1.5<T<300 respectively. ESR parameters provide direct evidence for vibrational behavior but not ions. These results are interpreted light recent discussions about relaxation cage systems. In particular, La0.9Gd0.1Pt4Ge12...

In this work we present an Electron Spin Resonance (ESR) study on La-doped EuFe2As2 aiming to further understand the coupling of localized spin states and itinerant electrons in these systems. The temperature dependence Eu2+ ESR linewidth, g-value intensity was investigated for both monocrystalline powdered samples. Our results confirm suggestion previous experiments pure compound [1], that SDW transition dramatically changes between states. addition, found a peculiar dome like shape...

Electron Spin Resonance (ESR) experiments in the filled Cei1-xYbxFe4P12 (x ≲ 0.0023) skutterudite compounds of Th cubic symmetry (Im3) reveal coexistence two distinct Yb3+ sites with large difference their site occupation, hyperfine interaction and temperature dependence ESR parameters. These results suggest a scenario where oversized (Fe2P3)4-cages Ce1-xYbxFe4P12 are occupied small number on-center-Yb3+ ions distribution highly off-center-Yb3+ions, rattling at ~1 GHz above ~20 GHz, respectively.

Ordered states in itinerant magnets may be related to magnetic moments displaying some weak local moment characteristics, as intermetallic compounds hosting transition metal coordination complexes. In this paper, we report on the Fe $K$-edge X-ray absorption spectroscopy (XAS) of $R$Fe$_{4}$Sb$_{12}$ ($R=$ Na, K, Ca, Sr, Ba), aiming at exploring electronic and structural properties octahedral building block formed by Sb ligands. We find evidence for strong hybridization between $3d$ $5p$...

We report evidence for a close relation between the thermal activation of rattling motion filler guest atoms and inhomogeneous spin dynamics Eu${}^{2+}$ spins. The is probed directly by means electron resonance (ESR), performed in both $X$-band ($\ensuremath{\approx}$$9.4$ GHz) $Q$-band ($\ensuremath{\approx}$34 frequencies temperature interval $4.2\phantom{\rule{0.28em}{0ex}}\text{K}\ensuremath{\lesssim}T\ensuremath{\lesssim}300$ K. A comparative study with ESR measurements on...