Micrometer thick soft magnetic films with magnetic moments restricted strictly in plane by negative magnetocrystalline anisotropy

Abstract

Stripe domains or any other type domain structures with part of their magnetic moments deviating from the film plane, which usually occur above a certain film thickness, are known problems that limit their potential applications for soft magnetic thin films (SMTFs). In this work, we report the growth of micrometer thick c-axis oriented hcp-Co84Ir16SMTFs with their magnetic moments restricted strictly in plane by negative magnetocrystalline anisotropy. Extensive characterizations have been performed on these films, which show that they exhibit very good soft magnetic properties even for our micrometer thick films. Moreover, the anisotropy properties and high-frequency properties were thoroughly investigated and our results show very promising properties of these SMTFs for future applications.

Effective reduction of the coercivity for Co$_{72}$Pt$_{28}$ thin film by exchange coupled Co$_{81}$Ir$_{19}$ soft layer with negative magnetocrystalline anisotropy

“…The base pressure before deposition was lower than 2×10 −5 Pa. For comparison reasons, ECC media systems with different SL compositions were also prepared with a similar fashion. To be exact, SL=Fe, Co and Co 100−x Ir x with x=23, 29 and 33 systems were prepared and these samples will be denoted as HL/(Fe,Co) and HL/SL (23,29,33), respectively. Note, that all Co 100−x Ir x with x=19, 23, 29 and 33 samples have the same crystal structure 30,31 .…”

“…Characterization of the magnetic properties were done with a vibrating sample magnetometer (VSM). Dynamic magnetic properties were measured with an electron spin resonance spectrometer (ESR) to determine the intrinsic magnetocrystalline anisotropy constant and the detailed procedure can be found in our previously published works 32,33 . These measurements were all done at room temperature and our samples were stored under vacuum when the measurements are done.…”

“…Here, positive MA means that the easy axis of the magnetic material is along its crystallographic c-axis and negative MA, on the other hand, means that the easy axis is within its ab-plane. Thus, by oriented-growth of the hcp-Co 81 Ir 19 (negative MA with x = 19) layer with its crystallographic c-axis parallel to the normal of the film surface, its magnetic moments can be restricted strictly in-plane by its negative MA, thus providing a very strong negative total in-plane anisotropy for our ECC media 32,33 . A series of samples with different SL thickness and composition were investigated and we will show that negative SL MA is more efficient in reducing the coercivity of the ECC media, thus our results agree with the theoretical prediction of Victora et al 12,29 and open a new playground for further improvements of the magnetic properties of the ECC media for high density magnetic recording.…”

NMR Profiling of Reaction and Transport in Thin Layers: A Review

“…The reason to incorporate thin layers can be manifold, for example, down-scaling [ 14 ], introducing novel technologies [ 15 ], increasing performance and stability. Another important feature when using thin polymer films is the ability to incorporate a huge variety of functional molecules which allow electrical [ 16 , 17 , 18 ], magnetic [ 19 ] or even color-like [ 20 ] like features in the thin layer. Performance and stability of these thin layers will be determined by their final structure and underlying physical processes.…”

Influence of additives on the magnetic damping constant of CoIr soft magnetic thin films with negative magnetocrystalline anisotropy*

“…[4] In our previous work, the damping constant of CoIr films has been investigated thoroughly with thickness, substrate temperature, and Ir content. [13] CoIr films with a certain Ir content exhibit strong negative magnetocrystalline anisotropy, which means that the c-plane of the hcp-CoIr crystal is the easy magnetization plane and the c-axis is the corresponding hard axis. [14] The properties enhance the high frequency magnetic properties and the critical film thickness for the Néel type domain wall changing into Bloch type, and strictly restrict the magnetic moments in-plane of micrometer thick soft magnetic thin films (SMTFs).…”