M. Viret

Very large spontaneous electric polarization in BiFeO3 single crystals at room temperature and its evolution under cycling fields

Electric polarization loops are measured at room temperature on highly pure BiFeO3 single crystals synthesized by a flux growth method. Because the crystals have a high electrical resistivity, the resulting low leakage currents allow the authors to measure a large spontaneous polarization in excess of 100μCcm−2, a value never reported in the bulk. During electric cycling, the slow degradation of the material leads to an evolution of the hysteresis curves eventually preventing full saturation of the crystals.

Electric-field-induced spin flop in BiFeO3 single crystals at room temperature.

Bismuth ferrite, BiFeO3, is the only known room-temperature magnetic ferroelectric material. We demonstrate here, using neutron scattering measurements in high quality single crystals, that the antiferromagnetic and ferroelectric order parameters are intimately coupled. Initially in a single ferroelectric state, our crystals have a canted antiferromagnetic structure describing a unique cycloid. Under electrical poling, polarization reorientation induces a spin flop. We argue here that the coupling between the two orders may be stronger in the bulk than in thin films where the cycloid is absent.

Influence of parasitic phases on the properties of BiFeO3 epitaxial thin films

We have explored the influence of deposition pressure and temperature on the growth of BiFeO3 thin films by pulsed laser deposition onto (001)-oriented SrTiO3 substrates. Single-phase BiFeO3 films are obtained in a region close to 10−2mbar and 580°C. In nonoptimal conditions, x-ray diffraction reveals the presence of Fe oxides or of Bi2O3. We address the influence of these parasitic phases on the magnetic and electrical properties of the films and show that films with Fe2O3 systematically exhibit a ferromagnetic behavior, while single-phase films have a low bulklike magnetic moment. Conductive-tip atomic force microscopy mappings also indicate that Bi2O3 conductive outgrowths create shortcuts through the BiFeO3 films, thus preventing their practical use as ferroelectric elements in functional heterostructures.

Comparative measurements of inverse spin Hall effects and magnetoresistance in YIG/Pt and YIG/Ta

We report on a comparative study of spin Hall related effects and magnetoresistance in YIG

Light-induced size changes in BiFeO3 crystals

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Colossal magnetoresistance of the variable range hopping regime in the manganites

Pt and YIG

Multiferroicity and hydrogen-bond ordering in (C2H5NH3)2CuCl4 featuring dominant ferromagnetic interactions

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Full control of the spin-wave damping in a magnetic insulator using spin-orbit torque.

Ta bilayers. These combined measurements allow to estimate the characteristic transport parameters of both Pt and Ta layers juxtaposed to yttrium iron garnet (YIG): the spin mixing conductance

Thickness-dependent structural and electrical properties of multiferroic Mn-doped BiFeO3 thin films grown epitaxially by pulsed laser deposition

{G}_{\ensuremath{\uparrow}\ensuremath{\downarrow}}

Magnetotransport properties of Fe3O4 epitaxial thin films: Thickness effects driven by antiphase boundaries

at the YIG