Magnetic characterization of microscopic particles by MO‐SNOM

Schoenmaker, J.; Lancarotte, Marcelo Shiroma; Seabra, Antônio Carlos; Souche, Y.; Santos, Amilton M.

doi:10.1111/j.0022-2720.2004.01303.x

Cited by 13 publications

(9 citation statements)

References 10 publications

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“…Utilizing a transverselike MOKE configuration, our MO-SNOM setup allows us to measure accurate LHLs and to obtain MO differential susceptibility ͑MODS͒ images. 4 The MODS is proportional to the local magnetic susceptibility under a weak oscillating magnetic field H ac . The LHLs are obtained by positioning the tip just above the examined region.…”

Section: Local Hysteresis Loop Measurements By Magneto-optical Scannimentioning

confidence: 99%

Local hysteresis loop measurements by magneto-optical scanning near-field optical microscope

Schoenmaker

Santos

Seabra

et al. 2005

Journal of Applied Physics

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We performed magnetic-field-induced experiments on micron-sized patterned Co70.4Fe4.6Si15B10 square thin-film elements with in-plane magnetic anisotropy by magneto-optical scanning near-field optical microscopy (MO-SNOM) with a spatial resolution better than 200nm. Markedly different local hysteresis loops (LHLs) were measured on selected positions in one element. Some LHLs presented an unusual shape intrinsic of local magnetic-field-induced process. Comparison of the MO-SNOM imaging results with high-resolution far-field Kerr microscopy has confirmed the local character of the MO-SNOM measurements. This has also helped us to understand the unusual LHLs shapes as related to the field-induced rearrangement of the domain structure within the square element during the magnetization process. The magnetic structure in small field is well described by two overlapping four-domain flux-closure configurations that are well modeled by micromagnetic calculations.

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Section: Local Hysteresis Loop Measurements By Magneto-optical Scannimentioning

confidence: 99%

Local hysteresis loop measurements by magneto-optical scanning near-field optical microscope

Schoenmaker

Santos

Seabra

et al. 2005

Journal of Applied Physics

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“…Aperture-type SNOMs using optical probe having an aperture on top of tapered optical fiber with metal were extensively studied, because it was considered that polarization properties were maintained and background signal was relatively small. Magneto-optical (MO) measurements that measure optical responses of magnetic materials for circular polarization are one of the most important purpose at that time [11][12][13][14][15][16][17][18][19][20][21][22], because size of magnetic recording marks had became smaller than the wavelength of the visible light. Several groups use aperture-type optical fiber probes collecting the evanescent wave, which is referred to as a transmission-mode MO-SNOM.…”

Section: Introductionmentioning

confidence: 99%

Polarization Properties in Apertureless-Type Scanning Near-Field Optical Microscopy

Ishibashi¹,

Cai²

2016

Nano Online

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Polarization properties of apertureless-type scanning near-field optical microscopy (a-SNOM) were measured experimentally and were also analyzed using a finite-difference time-domain (FDTD) simulation. Our study reveals that the polarization properties in the a-SNOM are maintained and the a-SNOM works as a wave plate expressed by a Jones matrix. The measured signals obtained by the lock-in detection technique could be decomposed into signals scattered from near-field region and background signals reflected by tip and sample. Polarization images measured by a-SNOM with an angle resolution of 1°are shown. FDTD analysis also reveals the polarization properties of light in the area between a tip and a sample are p-polarization in most of cases.

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“…Já para a caracterização das propriedades magnéticas locais utilizamos a técnica do Microscópio Ótico de Varredura de Campo Próximo no Modo Magnetoótico (SNOM-MO). Esta é uma microscopia magnética que apresenta algumas vantagens quando comparada com a técnica do MFM, sendo que a principal delas é que sua sonda de varredura é não magnética e que portanto, não influencia na tomada dos resultados experimentais [Sch04]. O SNOM-MO se demonstrou nos últimos anos uma poderosa ferramenta para obter informações magnéticas locais tanto através de medidas de susceptibilidade diferencial [Sch06], como através de ciclos de histerese locais [Sch03,Sch05].…”

Section: Figura 12: Estudo De Vórtices Magnéticos Em Um Disco De Perunclassified

“…Esta é uma microscopia magnética que apresenta algumas vantagens quando comparada com a técnica do MFM, sendo que a principal delas é que sua sonda de varredura é não magnética e que portanto, não influencia na tomada dos resultados experimentais [Sch04]. O SNOM-MO se demonstrou nos últimos anos uma poderosa ferramenta para obter informações magnéticas locais tanto através de medidas de susceptibilidade diferencial [Sch06], como através de ciclos de histerese locais [Sch03,Sch05]. É justamente lançando mão dessa segunda ferramenta que foi possível fazer um mapeamento dos ciclos de histerese em um objeto microestruturado, onde o deslocamento entre cada ponto de medida foi de 125nm.…”

Section: Figura 12: Estudo De Vórtices Magnéticos Em Um Disco De Perunclassified

Estudo das propriedades magnéticas de um objeto microestruturado através do SNOM-MO

Pojar¹

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Dedico este trabalho aos meus pais e à minha família.iii AgradecimentosGostaria de agradecer as várias pessoas que contribuíram de forma direta ou indireta para a realização deste trabalho.Em especial, ao Toninho, pela oportunidade e voto de confiança para a realização deste trabalho, pela orientação e dedicação, sugestões e conselhos sempre dados de modo preciso e sempre pacientes, e principalmente pela sua amizade; Ao Seabra, pelos ensinamentos em sua área de pesquisa e principalmente pela paciência e insistência nas horas de dificuldade; Ao Jeroen, eterno amigo, que ensinou todos os detalhes e procedimentos no manuseio do SNOM de forma precisa e carinhosa; À Alessandro, Angela, Regina, Luiz, Narcizo, companheiros de trabalho que desde o início acompanharam os meus primeiros passos; À Gabriel, Simone, Gilderlon e Erick, valeu pela companhia, amizade e brincadeiras que tornaram o convívio no Laboratório mais carinhoso e agradável; Ao Sergio, Marcelo, Iran, Paulo e Marcos, obrigada pela predisposição e paciência por me ajudarem sempre; Aos meus Pais, minha avó, e meus irmãos (Renata, Camila e Divino), pelo apoio incondicional durante todos esses anos, desde os meus primeiros passos e em todos os momentos bons e ruins; pela infinita paciência e compreensão nas várias vezes que estive ausente, por ser o que vocês são... Sem vocês seria impossível essa minha caminhada. Optical Microscope (SNOM-MO) falls in this context due to be a technique of microscopy with high spatial resolution and magnetic sensitivity, estimated to be ∆M = 2 x 10 -12 emu. In contrast to traditional optical microscopes, SNOM deals with evanescent electromagnetic radiation and, consequently, the resolution is no longer limited by the Rayleigh criterion.The SNOM-MO is a powerful tool to obtain local magnetic information through differential susceptibility and local hysteresis loops. Using this last technique, an experimental micromagnetic mapping was made for the magnetization vector on a square amorphous CoFeSiBNb object. The experimental results obtained provided information about the two chiralities existing in its closure magnetic domain structure, whose behavior is determined mainly by the shape anisotropy. The study also showed that pinnings generated by defects on surface´s object exerted great influence on the dynamic of the magnetization vectors. Due to the large amount of local magnetic information, this kind of study becomes a potential background for the development of more accurate and complete theoretical models.The experimental results demonstrate resolution better than 125 nm. This study has allowed us to access intrinsic magnetic behaviors that motivated an interesting discussion about magnetic pinnings, rotation of magnetization, reversal magnetic fields and local anisotropy.In addition, also special attention was given to the optimization of instrumental technique in order to make the SNOM-MO a measurement instrument with nanometer resolution. Among these efforts we emphasize the production of tips by FIB technique and the int...

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Magnetic characterization of microscopic particles by MO‐SNOM

Cited by 13 publications

References 10 publications

Local hysteresis loop measurements by magneto-optical scanning near-field optical microscope

Local hysteresis loop measurements by magneto-optical scanning near-field optical microscope

Polarization Properties in Apertureless-Type Scanning Near-Field Optical Microscopy

Estudo das propriedades magnéticas de um objeto microestruturado através do SNOM-MO

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