J.-m. Broto - Academia.edu (original) (raw)

Papers by J.-m. Broto

Research paper thumbnail of The band structure of Cd3P2 in the presence of a magnetic field

physica status solidi (b), 1982

The band structure of Cd3P2 is presented on the basis of Bodnar's model which is extended by ... more The band structure of Cd3P2 is presented on the basis of Bodnar's model which is extended by Wallace in presence of magnetic field. The oscillations of the Fermi level with magnetic field are calculated and it is found that the amplitude of the oscillations in Cd3P2 is larger than in Cd3As2. The effect of the so‐called free‐electron term is included in the calculation of the g‐factor and cyclotron effective mass. The correction due to the free‐electron term in the g‐factor is smaller (gf ≪ 2) than anticipated and depends on energy. Another interesting result of the calculation is that there is linear relationship between cyclotron effective mass and energy.

Research paper thumbnail of S=12 antiferromagnetic Heisenberg chain with staggered fields: Copper pyrimidine and copper benzoate using the density matrix renormalization group for transfer matrices

Research paper thumbnail of Quasi-static pulsed high magnetic field used to study magnetic properties of semimagnetic semiconductors

Physica B: Condensed Matter, 1989

The analysis of high magnetic field magnetization of semimagnetic semiconductors provides a direc... more The analysis of high magnetic field magnetization of semimagnetic semiconductors provides a direct determination of the exchange constants between magnetic ions. Supported by a review of the results obtained in pulsed magnetic fields up to 42 T for II1-xMnx and Pb1-xGdxTe SMSC, we emphasize the importance to use a quasi-static magnetic field with the highest possible value.

Research paper thumbnail of Magnetoconductance of amorphous Yx-Si1−x alloys near the metal-insulator transition

Journal of Non-Crystalline Solids, 1990

... OF AMORPHOUS Yx-Sil.x ALLOYS NEAR THE METAL-INSULATOR TRANSITION M. SANQUER, R. TOURBOT, B. B... more ... OF AMORPHOUS Yx-Sil.x ALLOYS NEAR THE METAL-INSULATOR TRANSITION M. SANQUER, R. TOURBOT, B. BOUCHER, JM BROTO', H. RAKOTO* Service de ... gives us the minimal value for He and the order of magnitude for spin-orbit scattering in all the sam-ples #I to ...

Research paper thumbnail of Upper critical field ofBa1−xKxBiO3single crystals

Research paper thumbnail of Anomalous Temperature Dependence of the Upper Critical Magnetic Field in Electron-Doped High-Temperature Superconductor

Solid State Phenomena, 2015

We present resistivity measurements of the upper critical field as a function of temperature for ... more We present resistivity measurements of the upper critical field as a function of temperature for Nd2-xCexCuO4+δ/SrTiO3 single crystal films near antiferromagnetic-superconducting phase boundary (x = 0.14) in magnetic fields up to 90kOe at temperatures down to 0.7K. The data are well described by a two-band/two-gap model for a superconductor in the dirty limit.

Research paper thumbnail of Magnetic ordering and hopping conductivity in a quasi-one dimensional Ca3Co2O6 single crystal

Research paper thumbnail of Magnetoresistance of a Si-MOSFET structure in a parallel magnetic field

Physica B: Condensed Matter, 2004

Research paper thumbnail of Giant Magnetoresistance of (001) Fe / (001) Cr Superlattices

MRS Proceedings, 1989

ABSTRACTWe recently reported the observation of a very large magnetoresistance in (001)Fe/(001)Cr... more ABSTRACTWe recently reported the observation of a very large magnetoresistance in (001)Fe/(001)Cr superlattices grown by MBE. The magnetoresistance is found to be very large for thin Cr layers. We ascribe this magnetoresistance to a magnetic gate effect.We recently reported the observation of a very large magnetoresistance in (001)Fe/(001)Cr superlattices with thin Cr layers [1]. A large magnetoresitance has also been observed in Fe/Cr/Fe sandwhiches [2]. In both cases, for Cr layers thinner than about 30 Å an antiparallel coupling of the magnetization of neighbor Fe layers is indicated by magnetic, magneto-optic and light scattering measurements [1–3]. It thus turns out that the large magnetoresistance os associated with the change to parallel alignment in an applied field. In this paper, we present new data on the magnetic and transport properties of Fe/Cr superlattics and we concentrate on the discussion of the microscopic origin of the magnetoresistance

Research paper thumbnail of Surface effects on the magnetic properties of ultrafine cobalt particles

Research paper thumbnail of High-field ferromagnetic resonance in fine particles

Physica B: Condensed Matter, 1998

We investigate high-field ferromagnetic resonance of superparamagnetic particles with uniaxial an... more We investigate high-field ferromagnetic resonance of superparamagnetic particles with uniaxial anisotropy. In this case, since the field is large enough to saturate the magnetization, the thermal orientational fluctuations of the magnetic moment of the particle are negligible. Thus, we derive the dynamic susceptibility of the system on the basis of an independent particle model. High-field ferromagnetic resonance has been performed on fine cobalt particles. The analysis of the spectra obtained at different frequencies allows us to estimate the effective magnetic anisotropy, the gyromagnetic ratio, and the transverse relaxation time.

Research paper thumbnail of Band parameters of FeSi single crystals determined by magnetic measurements

Research paper thumbnail of H–T magnetic phase diagrams of electron-doped Sm1−xCaxMnO3

Physica B: Condensed Matter, 2001

Research paper thumbnail of High magnetic field study of lattice and magnetic effects on the charge-melting transition in L1/2Ca1/2MnO3 perovskites

Research paper thumbnail of Trigonal field acting at the Cr^{3+} ^{2}E states in ruby from magneto-optical measurements under high pressure

Research paper thumbnail of Magnetic properties of β-FeSi2 single crystals

Research paper thumbnail of Magnetic properties of nanometric nickel particles

Solid State Communications, 1993

Research paper thumbnail of High-field Zeeman and Paschen-Back effects at high pressure in oriented ruby

Research paper thumbnail of Shubnikov-De Haas Effect and Cyclotron Resonance in p-CdSb

physica status solidi (b), 1984

Research paper thumbnail of Upper critical field of Ba1−χKχBiO3 single crystal

Physica C: Superconductivity, 1993

We measured the upper critical field Hc2 on Ba1-chiKchiBiO3 (0.35&amp... more We measured the upper critical field Hc2 on Ba1-chiKchiBiO3 (0.35<chi<0.40) single crystal down to 2 K in pulsed magnetic fields up to 35 T. Resistive transitions in the magnetic field systematically shift as the temperature decreases and the varrho-H curves saturate for high enough magnetic field strength. The initial slope of the upper critical field (dHc2/dT)Tc is -0.5 T/K. As

Research paper thumbnail of The band structure of Cd3P2 in the presence of a magnetic field

physica status solidi (b), 1982

The band structure of Cd3P2 is presented on the basis of Bodnar's model which is extended by ... more The band structure of Cd3P2 is presented on the basis of Bodnar's model which is extended by Wallace in presence of magnetic field. The oscillations of the Fermi level with magnetic field are calculated and it is found that the amplitude of the oscillations in Cd3P2 is larger than in Cd3As2. The effect of the so‐called free‐electron term is included in the calculation of the g‐factor and cyclotron effective mass. The correction due to the free‐electron term in the g‐factor is smaller (gf ≪ 2) than anticipated and depends on energy. Another interesting result of the calculation is that there is linear relationship between cyclotron effective mass and energy.

Research paper thumbnail of S=12 antiferromagnetic Heisenberg chain with staggered fields: Copper pyrimidine and copper benzoate using the density matrix renormalization group for transfer matrices

Research paper thumbnail of Quasi-static pulsed high magnetic field used to study magnetic properties of semimagnetic semiconductors

Physica B: Condensed Matter, 1989

The analysis of high magnetic field magnetization of semimagnetic semiconductors provides a direc... more The analysis of high magnetic field magnetization of semimagnetic semiconductors provides a direct determination of the exchange constants between magnetic ions. Supported by a review of the results obtained in pulsed magnetic fields up to 42 T for II1-xMnx and Pb1-xGdxTe SMSC, we emphasize the importance to use a quasi-static magnetic field with the highest possible value.

Research paper thumbnail of Magnetoconductance of amorphous Yx-Si1−x alloys near the metal-insulator transition

Journal of Non-Crystalline Solids, 1990

... OF AMORPHOUS Yx-Sil.x ALLOYS NEAR THE METAL-INSULATOR TRANSITION M. SANQUER, R. TOURBOT, B. B... more ... OF AMORPHOUS Yx-Sil.x ALLOYS NEAR THE METAL-INSULATOR TRANSITION M. SANQUER, R. TOURBOT, B. BOUCHER, JM BROTO', H. RAKOTO* Service de ... gives us the minimal value for He and the order of magnitude for spin-orbit scattering in all the sam-ples #I to ...

Research paper thumbnail of Upper critical field ofBa1−xKxBiO3single crystals

Research paper thumbnail of Anomalous Temperature Dependence of the Upper Critical Magnetic Field in Electron-Doped High-Temperature Superconductor

Solid State Phenomena, 2015

We present resistivity measurements of the upper critical field as a function of temperature for ... more We present resistivity measurements of the upper critical field as a function of temperature for Nd2-xCexCuO4+δ/SrTiO3 single crystal films near antiferromagnetic-superconducting phase boundary (x = 0.14) in magnetic fields up to 90kOe at temperatures down to 0.7K. The data are well described by a two-band/two-gap model for a superconductor in the dirty limit.

Research paper thumbnail of Magnetic ordering and hopping conductivity in a quasi-one dimensional Ca3Co2O6 single crystal

Research paper thumbnail of Magnetoresistance of a Si-MOSFET structure in a parallel magnetic field

Physica B: Condensed Matter, 2004

Research paper thumbnail of Giant Magnetoresistance of (001) Fe / (001) Cr Superlattices

MRS Proceedings, 1989

ABSTRACTWe recently reported the observation of a very large magnetoresistance in (001)Fe/(001)Cr... more ABSTRACTWe recently reported the observation of a very large magnetoresistance in (001)Fe/(001)Cr superlattices grown by MBE. The magnetoresistance is found to be very large for thin Cr layers. We ascribe this magnetoresistance to a magnetic gate effect.We recently reported the observation of a very large magnetoresistance in (001)Fe/(001)Cr superlattices with thin Cr layers [1]. A large magnetoresitance has also been observed in Fe/Cr/Fe sandwhiches [2]. In both cases, for Cr layers thinner than about 30 Å an antiparallel coupling of the magnetization of neighbor Fe layers is indicated by magnetic, magneto-optic and light scattering measurements [1–3]. It thus turns out that the large magnetoresistance os associated with the change to parallel alignment in an applied field. In this paper, we present new data on the magnetic and transport properties of Fe/Cr superlattics and we concentrate on the discussion of the microscopic origin of the magnetoresistance

Research paper thumbnail of Surface effects on the magnetic properties of ultrafine cobalt particles

Research paper thumbnail of High-field ferromagnetic resonance in fine particles

Physica B: Condensed Matter, 1998

We investigate high-field ferromagnetic resonance of superparamagnetic particles with uniaxial an... more We investigate high-field ferromagnetic resonance of superparamagnetic particles with uniaxial anisotropy. In this case, since the field is large enough to saturate the magnetization, the thermal orientational fluctuations of the magnetic moment of the particle are negligible. Thus, we derive the dynamic susceptibility of the system on the basis of an independent particle model. High-field ferromagnetic resonance has been performed on fine cobalt particles. The analysis of the spectra obtained at different frequencies allows us to estimate the effective magnetic anisotropy, the gyromagnetic ratio, and the transverse relaxation time.

Research paper thumbnail of Band parameters of FeSi single crystals determined by magnetic measurements

Research paper thumbnail of H–T magnetic phase diagrams of electron-doped Sm1−xCaxMnO3

Physica B: Condensed Matter, 2001

Research paper thumbnail of High magnetic field study of lattice and magnetic effects on the charge-melting transition in L1/2Ca1/2MnO3 perovskites

Research paper thumbnail of Trigonal field acting at the Cr^{3+} ^{2}E states in ruby from magneto-optical measurements under high pressure

Research paper thumbnail of Magnetic properties of β-FeSi2 single crystals

Research paper thumbnail of Magnetic properties of nanometric nickel particles

Solid State Communications, 1993

Research paper thumbnail of High-field Zeeman and Paschen-Back effects at high pressure in oriented ruby

Research paper thumbnail of Shubnikov-De Haas Effect and Cyclotron Resonance in p-CdSb

physica status solidi (b), 1984

Research paper thumbnail of Upper critical field of Ba1−χKχBiO3 single crystal

Physica C: Superconductivity, 1993

We measured the upper critical field Hc2 on Ba1-chiKchiBiO3 (0.35&amp... more We measured the upper critical field Hc2 on Ba1-chiKchiBiO3 (0.35<chi<0.40) single crystal down to 2 K in pulsed magnetic fields up to 35 T. Resistive transitions in the magnetic field systematically shift as the temperature decreases and the varrho-H curves saturate for high enough magnetic field strength. The initial slope of the upper critical field (dHc2/dT)Tc is -0.5 T/K. As