Correlation of magnetic and magnetoresistive properties of nanoporous Co/Pd thin multilayers fabricated on anodized TiO2 templates

Abstract

In this study, we consider a technological approach to obtain a high perpendicular magnetic anisotropy of the Co/Pd multilayers deposited on nanoporous TiO2 templates of different types of surface morphology. It is found that the use of templates with homogeneous and smoothed surface relief, formed on silicon wafers, ensures conservation of perpendicular anisotropy of the deposited films inherent in the continuous multilayers. Also, their magnetic hardening with doubling of the coercive field is observed. However, inhomogeneous magnetic ordering is revealed in the porous films due to the occurrence of magnetically soft regions near the pore edges and/or inside the pores. Modeling of the field dependences of magnetization and electrical resistance indicates that coherent rotation is the dominant mechanism of magnetization reversal in the porous system instead of the domain-wall motion typical of the continuous multilayers, while their magnetoresistance is determined by electron-magnon scattering, similarly to the continuous counterpart. The preservation of spin waves in the porous films indicates a high uniformity of the magnetic ordering in the fabricated porous systems due to a sufficiently regular pores array introduced into the films, despite the existence of soft-magnetic regions. The results are promising for the design and fabrication of future spintronic devices.

Fundamentally Different Magnetoresistance Mechanisms in Related Co/Pd and Co/Pt Multilayers for Spintronic Applications

“…The negative MR effect in the Co/Pd MLs is identified to be realized via the magnon MR (MMR) mechanism. 9,[19][20][21] The positive MR effect in the Co/Pt MLs relates to the Lorentz MR (LMR) mechanism, 22,23) with the magnitude of the effect being atypically increased at RT. Both mechanisms are isotropic for the field rotation in zy plane.…”

ĐIỀU BIẾN DỊ HƯỚNG TỪ VÀ TRƯỜNG TRAO ĐỔI DỊCH THEO PHƯƠNG VUÔNG GÓC TRONG CÁC MÀNG ĐA LỚP [Co/Pd]-IrMn CÓ CẤU TRÚC NANO DẠNG ANTIDOT ARRAYS

“…7 erg/cm 3 ) [17] lớn hơn dị hướng từ của màng (Co/Pd 6,5×10 6 erg/cm 3 ) [18]. [19] khiến cho mẫu xốp bị "cứng" hơn so với mẫu màng phẳng [20], [21]. Khi có thêm lớp phản sắt từ IrMn, đường cong từ hóa đo ở nhiệt độ phòng trong cả hai mẫu màng phẳng và màng xốp [Co/Pd]-IrMn đều bị dịch về phía bên trái theo hướng của từ trường, thể hiện hiệu ứng trao đổi dịch theo phương vuông góc ở nhiệt độ phòng trong hệ vật liệu đã chế tạo.…”