Solid-phase equilibria in the MnTe-SnTe-Bi2Te3 pseudo-ternary system were experimentally investigated for the first time using powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). An isothermal section of the phase diagram at 500 degrees C was constructed. Three series of continuous solid solutions-(Mn/Sn)Bi2Te4, (Mn/Sn)Bi4Te7, and (Mn/Sn)Bi6Te10-with tetradymite-type structures were identified. In addition, boundary system compounds Sn3Bi2Te6, Sn2Bi2Te5, MnBi8Te13, MnBi10Te16, MnBi12Te19, and MnBi14Te22 exhibit extended homogeneity ranges with significant Mn <-> Sn substitution. Magnetic properties of partially Mn-substituted (Mn0.55Sn0.45Bi2Te4)(Bi2Te3)(m) (m = 4, 5) were examined using SQUID magnetometry and electron paramagnetic resonance (EPR). Preliminary results indicate competing ferro- and antiferromagnetic interactions persisting over large Mn-Mn distances (>6 nm) as suggested by the crystal structure, although no magnetic order is observed. A transition from 2D to 3D spin diffusion occurs with increasing temperature. The disorder of Mn atoms within such a tetradymite-type structure, being much discussed recently, is considered to be the likely cause of this persistence.

Dielectric and magnetoelectric (ME) studies were conducted on polycrystalline samples of the molecular spin triangle [Fe3O(O2CPh)6(py)3]ClO4·py (Fe3) and on its diamagnetic isostructural GaIII analogue (Ga3). Dielectric studies revealed a thermally activated process between approximately 15-60 K, attributed to the freezing-unfreezing of the crystallographically disordered pyridine solvates, with a paraelectric behavior above ∼68 K. Magnetoelectric studies revealed a second-order ME effect for Fe3, which remained significant above liquid-nitrogen temperatures. Similar experiments on Ga3 allowed to control for the instrumental baseline response and to confirm the origin of the signal as the ME effect of Fe3. The thermal evolution of the ME coupling coefficient (αME) showed no discontinuities around the temperature of the freezing-unfreezing processes, indicating that it is unrelated to them. These latter are assigned the disordered-diamagnetic sublattice consisting of the pyridine solvates and perchlorate counteranions. In turn, the ME coupling is assigned to the ordered-magnetic sublattice consisting of the Fe3 trinuclear cations. These results demonstrate that Fe3 can directly transform magnetic perturbations to electric signals at the single-molecule level, without the need of structural transformations or long-range magnetic ordering.

Electric fields represent an ideal means for controlling spins at the nanoscale and, more specifically, for manipulating protected degrees of freedom in multispin systems. Here we perform low-temperature magnetic far-IR spectroscopy on a molecular spin triangle (Fe3) and provide initial experimental evidence suggesting spin-electric transitions in polynuclear complexes. The co-presence of electric- and magnetic-dipole transitions, allows us to estimate the spin-electric coupling. Based on spin Hamiltonian simulations of the spectra, we identify the observed transitions and introduce the concept of a generalized exchange qubit. This applies to a wide class of molecular spin triangles, and includes the scalar chirality and the partial spin sum qubits as special cases. Polynuclear magnetic molecular complexes show promise as electrically controllable spin qubits. Here the authors report evidence of spin-electric transitions in the Fe3 triangle and propose it as a generalized exchange qubit, combining characteristics of spin-chirality and partial-spin sum qubits.

A diradical with engineered g-asymmetry was synthesized by grafting a nitroxide radical onto the [Y(Pc)2]⋅ radical platform. Various spectroscopic techniques and computational studies revealed that the electronic structures of the two spin systems remained minimally affected within the diradical system. Fluid-solution Electron Paramagnetic Resonance (EPR) experiments revealed a weak exchange coupling with |J| ~ 0.014 cm-1, subsequently rationalized by CAS-SCF calculations. Frozen solution continuous-wave (CW) EPR experiments showed a complicated and power-dependent spectrum that eluded analysis using the point-dipole model. Pulse EPR manipulations with varying microwave powers, or under varying magnetic fields, demonstrated that different resonances could be selectively enhanced or suppressed, based on their different tipping angles. In particular, Field-Swept Echo-Detected (FSED) spectra revealed absorptions of MW power-dependent intensities, while Field-Swept Spin Nutation (FSSN) experiments revealed two distinct Rabi frequencies. This study introduces a methodology to synthesize and characterize g-asymmetric two-spin systems, of interest in the implementation of spin-based CNOT gates.

Electric fields represent an ideal means for controlling spins at the nanoscale and, more specifically, for manipulating protected degrees of freedom in multispin systems. Here we perform low-temperature magnetic far-IR spectroscopy on a molecular spin triangle (Fe3) and provide the first experimental evidence of spin-electric transitions in polynuclear complexes. The co-presence of electric- and magnetic-dipole transitions, allows us to estimate the spin-electric coupling. Based on spin Hamiltonian simulations of the spectra, we identify the observed transitions and introduce the concept of a generalized exchange qubit. This applies to a wide class of molecular spin triangles, and includes the scalar chirality and the partial spin sum qubits as special cases.

A mixed-ligand phthalocyanine/porphyrin yttrium(III) radical double-decker complex (DD) was synthesized using the custom-made 5,10,15-tris(4-methoxyphenyl)-20-(4-((trimethylsilyl)ethynyl)phenyl)porphyrin. The trimethylsilyl functionality was then used to couple two such complexes into biradicals through rigid tethers. Glaser coupling was used to synthesize a short-tethered biradical (C1) and Sonogashira coupling to synthesize longer-tethered ones (C2 and C3). Field-swept echo-detected (FSED), saturation recovery, and spin nutation-pulsed electron paramagnetic resonance experiments revealed marked similarities of the magnetic properties of DD with those of the parent [Y(pc)2]• complex, both in the solid state and in CD2Cl2/CDCl3 4:1 frozen glasses. FSED experiments on the biradicals C2 and C3 revealed a spectral broadening with respect to the spectra of DD and [Y(pc)2]• assigned to the effect of dipolar interactions in solution. Apart from the main resonance, satellite features were also observed, which were simulated with dipole-dipole pairs of shortest distances, suggesting spin delocalization on the organic tether. FSED experiments on C1 yielded spectral line shapes that could not be simulated as the integration of the off-resonance echoes was complicated by field-dependent modulations. While, for all dimers, the on-resonance spin nutation experiments yielded Rabi oscillations of the same frequencies, off-resonance nutations on C1 yielded Rabi oscillations that could be assigned to a MS = -1 to MS = 0 transition within a S = 1 multiplet. The DFT calculations showed that the trans conformation of the complexes was significantly more stable than the cis one and that it induced a marked spin delocalization over the rigid organic tether. This "spin leakage" was most pronounced for the shortest biradical C1.

We built a broadband Electron Paramagnetic Resonance (EPR) spectrometer capable of field- and frequency sweep experiments under field-, microwave amplitude- and microwave frequency-modulation detection modes (HM, AM, and FM, respectively). The spectrometer is based on a coplanar waveguide (CPW) architecture, with the sample being deposited on top of the transmission line. We tested the functionality of this spectrometer by measuring a standard 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH) sample, and complex (NnBu4)2[Cu3(μ3-Cl)2(μ-pz)3Cl3] (1), drop-casted on the CPW. Complex 1 had been previously studied by conventional X-band EPR spectroscopy (Chem. - Eur. J., 2020, 26, 12769-1784), and comparison with the past studies validated the functionality of the spectrometer and confirmed the stability of the sample upon deposition. Moreover, our results highlighted the importance of surface effects and of the orientation of the microwave magnetic component B1 on the lineshapes of the recorded spectra.

A 16-line pattern has been theoretically predicted, but hitherto not reported, for the Electron Paramagnetic Resonance (EPR) spectrum of antiferromagnetically coupled CuII triangles experiencing isotropic exchange of isosceles magnetic symmetry. Now, the crystallization of such a triangular species and its X-ray structure determination in a polar space group, R3 (No. 146), has enabled its single crystal EPR study. Its detailed magnetic susceptibility, and X- and Q-band, powder and single crystal EPR spectroscopic study reveals the effect of molecular structure and of Dzyaloshinskii-Moriya interactions (DMI) on the g‖, g⊥ and A‖ parameters of the spectrum; DMI is considered for the first time in such a context. Moreover, careful analysis of the spectrum allows the deconvolution of two slightly different cocrystallized magnetic species.

FID-detected nutations of the antiferromagnetic crystal form of [Y(pc)2]˙ demonstrated that its radical spin can be coherently driven in its magnetically condensed undeuterated phase and at room temperature. Liquid-helium nutations revealed additional Rabi oscillations assigned to transitions within higher-multiplicity states of finite-sized chain fragments.

Mesoporous TiO2 films with enhanced photocatalytic activity in both UV and visible wavelength ranges were developed through a non-conventional atomic layer deposition (ALD) process at room temperature. Deposition at such a low temperature promotes the accumulation of by-products in the amorphous TiO2 films, caused by the incomplete hydrolysis of the TiCl4 precursor. The additional thermal annealing induces the fast recrystallisation of amorphous films, as well as an in situ acidic treatment of TiO2. The interplay between the deposition parameters, such as purge time, the amount of structural defects introduced and the enhancement of the photocatalytic properties from different mesoporous films clearly shows that our easily upscalable non-conventional ALD process is of great industrial interest for environmental remediation and other photocatalytic applications, such as hydrogen production.

By considering the intrinsic anisotropy, present in almost all magnetic systems, as a perturbation to the usual Zeeman term, we show that the spin-spin dipolar interaction also known as zero-field splitting (ZFS) leads to an extra geometrical phase in addition to the conventional Berry's phase. Furthermore, we suggest some ways to observe the energy shift in electron paramagnetic resonance spectra due to Berry's phase and how we can separate it from the conventional Zeeman Berry's phase. Copyright (C) EPLA, 2019

Two related iron(iii) and chromium(iii) spin-triangle molecular qubits show coherent driving of their spins, and decoherence that is not significantly affected by Dzyaloshikskii–Moriya spectral broadenings.

Two trinuclear CuII pyrazolato complexes with a Cu3(μ3-E)-core (E = O2- or OH-) and terminal nitrite ligands in two coordination modes were characterized crystallographically, spectroscopically, and electrochemically. One-electron oxidation of the μ3-O species produces a delocalized, mixed-valent, formally CuII2CuIII-nitrite, but no nitrate. In contrast, under reducing conditions-addition of PhSH as an electron and proton donor-both complexes mediate the reduction of nitrite, releasing NO.

Two molecular spin qubits are studied with pulsed electron paramagnetic resonance (EPR) spectroscopy under electric fields to assess their magnetoelectric (ME) couplings and electric spin control. [Fe3O(PhCOO)6(py)3]ClO4·py (Fe3) is characterized by strong Dzyaloshinskii-Moriya interactions (DMI) which induce important magnetoanisotropy, whereas the DMI in [Cr3O(PhCOO)6(py)3]ClO4·0.5py (Cr3) is 1-2 orders of magnitude weaker. Fe3 is observed to demonstrate a clear ME effect, whose intensity shows an unprecedented dependence on the molecular orientation within the electric field E (electroanisotropy) and on the relative orientations of the molecular z axis, the Zeeman field B0 and E (magnetoelectric anisotropy). The electric control in Fe3 is shown to be coherent, and the ME effect exhibits complex dynamics characterized by saturation and oscillatory effects. On the other hand, Cr3 exhibits no discernible ME effect, which correlates well with its negligible DMI.

Les proprietes magnetiques des materiaux sont exploitees dans de nombreuses applications : des plus classiques, composants electromecaniques, enregistrement magnetique, aux plus elaborees et futuristes, comme la refrigeration magnetique ou l'electronique de spin. Cet article introduit a notion de Liquide Ionique (LI) avec son extension aux composes incorporant des ions magnetiques (LIM). Une revue des LIM synthetises a ce jour est presentee, avec leurs principales proprietes physicochimiques, suivie d'une presentation des applications existantes, avec quelques perspectives pour leur etude et utilisation futures.