Antisymmetric Magnetoresistance in Magnetic Multilayers with Perpendicular Anisotropy

Abstract

While magnetoresistance (MR) has generally been found to be symmetric in applied field in non-magnetic or magnetic metals, we have observed antisymmetric MR in Co/Pt multilayers. Simultaneous domain imaging and transport measurements show that the antisymmetric MR is due to the appearance of domain walls that run perpendicular to both the magnetization and the current, a geometry existing only in materials with perpendicular magnetic anisotropy. As a result, the extraordinary Hall effect (EHE) gives rise to circulating currents in the vicinity of the domain walls that contributes to the MR.The antisymmetric MR and EHE have been quantitatively accounted for by a theoretical model. 75.60.Ch,

Influence of the substrate on structure and magnetic properties of Co–N thin films

“…Recently, it was shown that a minor variation of the thickness along the sample can induce this effect [28], but similar effects were also found at magnetization reversal of ferromagnets with an out-of plane magnetic anisotropy and explained by the movement of a domain wall located between the voltage probes, running perpendicular to both magnetization and current [29]. …”

Unusual magnetization reversal in [Co∕Pt]4 multilayers with perpendicular anisotropy

“…[5][6][7] The domain-wall motion mode dominates in the Pt/ Co/ Pt trilayers or ͓Co/ Pt͔ n multilayers with very small n, resulting in magnetically uniform bubble domains with changing sizes. 8,9 In contrast, the behavior of the ͓Co/ Pt͔ 4 multilayers with an intermediate n is between the above two limiting cases. When H is decreased from the positive saturation to −H T ͑point 2 in Fig.…”

“…5 At the other extreme, thin Pt/ Co/ Pt trilayers revealed very different behaviors, where magnetic domains expand by the propagation of smooth and well-defined domain walls. 8,9 Under a reversed field, the domain walls retract toward the nucleation centers. However, there has been little work on ͓Co/ Pt͔ n multilayers with an intermediate n, although several papers reported other materials with PMA and intermediate thickness.…”

“…[11][12][13] In this work, we have studied in detail the magnetization reversal behavior of ͓Co͑4 Å͒ /Pt͑10 Å͔͒ 4 multilayers with an intermediate n = 4, and revealed very unusual reversal behavior. The reversal has been studied macroscopically by vibrating-sample magnetometry ͑VSM͒, and microscopically by both magneto-optical Kerr effect ͑MOKE͒ microscopy 9,14,15 and magnetic force microscopy ͑MFM͒ imaging. 7,10 The first-order reversal curves ͑FORCs͒ for ͓Co/ Pt͔ n multilayers with an intermediate repeat number n = 4 are very different from those for ͓Co͑4 Å͒ /Pt͑7 Å͔͒ 50 multilayers.…”

Surface waves investigation in NiFe/Au/Co/Au multilayers by high-resolution Brillouin spectroscopy

“…A rapid increase in the memory operation frequency in modern computers and applications of ferromagnetic films to the microwave devices motivated special interest in their high-frequency dynamics [1,2]. Nowadays much attention is paid to thin multilayers deposited on silicon substrate [3][4][5]. From the application viewpoint, the knowledge of elastic properties of nanometric materials is of particular importance.…”