Polarized Neutron Reflectometry for the Analysis of Nanomagnetic Systems

Abstract

In recent years, polarized neutron reflectometry (PNR) has played an essential role for the exploration of magneto-and spintronic structures. Well known systems extensively studied include exchange coupled magnetic superlattices, exchange bias systems between ferromagnetic and antiferromagnetic films, exchange spring valves between soft and hard magnetic films, and more recently magnetic semiconductors and ferromagnetic Heusler alloy films and superlattices. In addition to studies of laterally extended layered systems, neutron scattering has now been applied to the exploration of periodic magnetic arrays, such as stripes and islands on the submicrometer scale. Although the competition with magneto-optics and X-ray resonant magnetic scattering (XRMS) has increased in recent years, there are some advantages PNR offers that are hard to challenge. One of those is the quantitative analysis of the data via fits to theoretical models based on the distorted wave Born approximation (DWBA), which accounts for both specular and off-specular scattering. The second one is spin flip (SF) scattering, which has no counterpart in XRMS. SF scattering probes magnetization fluctuations transverse to the mean magnetization direction and gives access to magnetic roughness and magnetic domain states. Specular and off-specular PNR work is exemplified by most recent work on spintronic materials and on patterned and functionalized magnetic layers.Index Terms-Lateral magnetic patterns, magnetic multilayers, magnetic nanostructure, magnetization reversal, polarized neutron reflectometry.

Unveiling structural, chemical and magnetic interfacial peculiarities in ε-Fe2O3/GaN (0001) epitaxial films

“…The important technical aspects of our PNR experiment are described below, while the details of methodology can be found elsewhere 28,29 . Neutron reflectometry experiments were performed at the instruments D17 30 (ILL, Grenoble, France) and BL17 SHARAKU 31 (J-PARC MLF, Tokai, Japan) in polarized time-of-flight mode.…”

Origin of superconductivity at nickel-bismuth interfaces

“…Careful fitting to the two obtained reflectivity curves in PNR allows the extraction of depth dependent magnetization and structure. PNR is widely employed in the successful characterization of spintronic materials [24] and is particularly useful in this study due to the large SLD contrast between the Ni and Bi layers. The sample is annealed repeatedly at 70 • C. Films are loaded at room temperature and cooled in an 0.2 T field to 10 K where we perform PNR measurements.…”

Self-Assembly of Magnetic Nanoparticles in Ferrofluids on Different Templates Investigated by Neutron Reflectometry

“…Additionally, magnetic force microscopy is frequently used for determining the properties of magnetic NPs assembled on a surface [ 29 , 36 , 39 ]. In recent years, neutron reflectometry and small angle neutron scattering (SANS) have proven to be indispensable methods for characterizing the spin configurations of these nanoparticle systems in detail, with nanometer-scale resolution [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ].…”