Influence of the magnetic field sweeping rate on magnetic transitions in synthetic ferrimagnets with perpendicular anisotropy

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Giant areas of enhanced conductivity and percolation threshold

AFM, MFM, phase conrast measurements of azolectin bilayer lipid membrane with magnetic nanoparticle

Giant areas of enhanced conductivity and percolation threshold

AFM, MFM, phase conrast measurements of azolectin bilayer lipid membrane with magnetic nanoparticle

Giant areas of enhanced conductivity and percolation threshold

AFM, MFM, phase conrast measurements of azolectin bilayer lipid membrane with magnetic nanoparticle

Giant areas of enhanced conductivity and percolation threshold

AFM, MFM, phase conrast measurements of azolectin bilayer lipid membrane with magnetic nanoparticle

Giant areas of enhanced conductivity and percolation threshold

AFM, MFM, phase conrast measurements of azolectin bilayer lipid membrane with magnetic nanoparticle

Strong magnetocaloric effect induced by spin reorientation transitions in epitaxial Ho thin films

International audienceMagnetocaloric effect (MCE) in an antiferromagnetic holmium (Ho) film is studied near the spin reorientation temperatures. A series of magnetization isotherms from 60 to 150 K around the Néel temperature, T N ≈ 130 K were recorded for both in-plane and out-of-plane magnetic field orientations. A change in entropy, S M of-5 J/kgK was found near T N for an in-plane field orientation. A large change in S M of −11.8 J/kg K due to a fan-helix spin transition at T = 90 K is observed for an in-plane field orientation. Spin transition at both T N and at the fan-helix transition exhibit larger MCE in the in-plane field orientations in comparison with the perpendicular orientation. The value of the refrigerant capacity extracted from the temperature dependence of S M (T) is found to be larger for the "in-plane" orientation by a factor of two

Ferromagnetic resonance in monocrystalline spin valves CoFeB/Ta/CoFeB and CoFeB films with perpendicular magnetic anisotropy

International audienceOrientation dependences of ferromagnetic resonance in a MgO/CoFeB/MgO/Ta film with one ferromagnetic layer (monolayer) and in a MgO/CoFeB/Ta/CoFeB/MgO/Ta spin valve containing two single crystal ferromagnetic CoFeB layers divided by a nonmagnetic Ta layer (bilayer) were investigated. Analysis of the orientation dependences of the structures with perpendicular magnetic anisotropy allowed calculating constants of magnetic anisotropy and damping factors. Physical reasons underlying the differences between these parameters in one-and two-layered structures are discussed

Impact of minor hysteresis loops in integrated inductors with ferromagnetic films

Integration of inductors on silicon chips is becoming more and more relevant for monolithic electronic applications. In this Letter, we investigate the impact of minor hysteresis loops in an integrated inductor with spiral geometry sandwiched between two soft magnetic layers made of MoNiFe/Cr multilayers. Despite high magnetic susceptibility and low coercivity of optimized multilayers, we find that the inductance is strongly dependent on the AC voltage applied to the device, showing a bell-shaped behavior. Comparing the measured inductance with magneto-optical Kerr effect and vibrating sample magnetometry measurements, we show that the low-signal behavior is limited by domain wall pinning/depinning, which determine the effective susceptibility associated with minor hysteresis loops driven by the applied AC voltage