Magnetic Properties Of Ferromagnetic Films Research Articles

Thickness dependent magnetic properties of ferromagnetic films (Fe, Co) interfaced with Ta

In the present work, magnetic properties of ferromagnetic films viz. Co and Fe interfaced with Ta have been studied using magneto-optical Kerr effect (MOKE), X-ray reflectivity (XRR) and soft X-ray absorption spectroscopy (SXAS) on wedge shaped samples. Thickness of ferromagnetic film at different points of wedge sample as determined from XRR were employed to study the evolution of magnetic properties with increasing film thickness using MOKE measurements. Co film exhibits a uniaxial magnetic anisotropy on Ta which varies as a function of increasing film thickness, while no thickness dependent magnetic anisotropy has been observed for Fe film grown on Ta. The variation of coercivity with increasing film thickness is in agreement with the observed variation of magnetic anisotropy. SXAS measurements qualitatively support alloying / intermixing at interface. Thicknesses of interfacial magnetic dead layer as seen from variation of Kerr intensity with film thickness is relatively higher for Co as compared to Fe, while interfaced with Ta.

Coercivity enhancement in V2O3/Ni bilayers driven by nanoscale phase coexistence

We studied the temperature dependence of coercivity and magnetization of V2O3/Ni bilayers across the Structural Phase Transition in V2O3. We found a coercivity peak that coincides with the V2O3 phase transition on top of an overall increase of the coercivity with decreasing temperature. We propose that this sharp increase arises from a length scale competition between magnetic domains of Ni and phase coexistence during the V2O3 phase transition. This model is supported by micromagnetic simulations and shows that magnetic properties of ferromagnetic films are strongly affected by a proximal first order phase transition.

Influence of the microcrystalline structure on the magnetic properties of ferromagnetic films and structures on their base

This paper presents the results of investigating the crystal structure of thin films of the Co40Fe60 composition obtained by magnetron sputtering on their magnetic properties and properties of ferromagnetic nanostructures formed from these films using the optical and electron lithography. It has been found experimentally that magnetic properties of the structures depend on the crystalline-grain sizes, which can be controlled by means of deposition of additional buffer layers of various materials ∼1 nm thick on the substrate under the ferromagnetic film. It has been shown that the crystallite size can be the main factor that determines the minimal lateral sizes of the structures with specified magnetic properties, which are formed from thin ferromagnetic films.

Effects of mechanical contact stress on magnetic properties of ferromagnetic film

Mechanical and magnetic degradation of ferromagnetic films under contact stress was systematically investigated through novel experiments and analytical simulations. Permalloy (Ni80Fe20) film was deposited onto silicon substrate, and two different thicknesses of permalloy film (50 nm for sample A and 300 nm for sample B) were examined in this study. Magnetic properties were obtained from B-H loop tracer hysteresis measurement, while the mechanical properties (i.e., hardness and elastic modulus) were measured using nanoindentation techniques. It was observed that the 50 nm thick permalloy film showed weaker magnetic strength (lower coercivity and saturation magnetic flux values) and lower hardness than the 300 nm thick permalloy film. To apply mechanical contact stress on the permalloy film samples, nanoscratch experiments were performed using ramp and constant loading scratch profiles. Then, the resulting mechanical degradation (surface physical damage) of the two samples was determined from atomic force microscope measurements, and the corresponding magnetic degradation was analyzed using magnetic force microscope measurements. It was found that the magnetic degradation was more sensitive to the applied contact stress than the mechanical degradation. Comparing the two permalloy film samples, it was observed that the 50 nm thick permalloy film showed more magnetic degradation under the same contact stress, which could be attributed to its lower material strength.

On the spin-wave theory of thin ferromagnetic films

The magnetic properties of ferromagnetic films have been investigated within a modified spin-wave theory. The non-uniform magnetization distribution is calculated, and the Curie temperature demonstrates a sharp decrease with decreasing L. The case of very thin films (few atomic layers) is considered within a self-consistent approach. In this case dynamic and kinematic interactions of magnons turn out to be important.

Elastic tension effect on magnetic properties of ferromagnetic films: V A Bouravikhin and V G Kazakov,Czech J Phys, B 21 (4/5), 1971, 375–383.

Elastic tension effect on magnetic properties of ferromagnetic films: V A Bouravikhin and V G Kazakov,Czech J Phys, B 21 (4/5), 1971, 375–383.

Elastic tension effect on magnetic properties of ferromagnetic films

The present work describes the results achieved in investigating the influence of mechanical stresses on the processes of quasi-static magnetization reversal, the dynamic characteristics and the creep of the domain walls of Fe-Ni films with Ni content from 60% to 90% and the thickness from 150 A to 3000 A.