A Kerr magnetometer using Faraday modulation technique

Hornauer, H.; Atmono, Tri Marji; Röll, K.

doi:10.1016/0304-8853(90)90621-v

Cited by 16 publications

(6 citation statements)

References 2 publications

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“…After preparation, the samples were cooled down to 130 K, and then slowly warmed up to 165 larger than the rotation K ), and in polar fields the rotation K of the polar effect ͑larger than ⑀ K in this case͒. Using a compensation technique, 18 both ⑀ K and K were measured in absolute units. Temperatures were measured with a relative accuracy of 1 K, and an absolute accuracy of about 10 K, using a thermocouple fixed to the sample holder.…”

mentioning

confidence: 99%

Perpendicular magnetization and dipolar antiferromagnetism in double layer nanostripe arrays of Fe(110) on W(110)

Hauschild

Gradmann

Elmers

1998

Applied Physics Letters

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Fe͑110͒ nanostripe arrays, consisting of alternating monolayer and double layer stripes, have been grown by step flow on vicinal W͑110͒ substrates. The magnetic easy axis switches from in-plane in the monolayer to perpendicular in the double layer stripes. The data strongly suggest that magnetostatic interactions induce antiferromagnetic order in the double layer nanostripe array. It can be switched into a ferromagnetic arrangement by low external fields.The progress in the field of epitaxial magnetic films, including the discovery of indirect exchange coupling 1-3 and giant magnetoresistance ͑GMR͒, 4,5 is based on techniques to control perpendicular profiles-both of composition and of magnetic properties-on a nanoscale. Recently, there has been increased interest in extending those concepts from perpendicular to lateral magnetic nanostructures-that means to two-dimensional arrays of magnetic nanowires or nanostripes-prepared either by lithographic techniques 6 or by self-organization on grooved 7,8 or on vicinal single crystal substrates. 9-11 A promising candidate for pronounced magnetoresistance would be given by a film containing an array of antiferromagnetically coupled magnetic nanowires, which could be switched from antiferromagnetic towards ferromagnetic order by low magnetic fields. For the case of perpendicularly magnetized nanowires, the antiferromagnetic coupling would be provided by magnetostatic interaction. The aim of the present letter is to show that arrays of pseudomorphic double-layer ͑DL͒ nanostripes of Fe͑110͒ on W͑110͒, prepared on vicinal W͑110͒ substrates, present just this type of magnetic order. The DL stripe system then resembles a system of magnetic stripe domains in a homogeneous film of perpendicular anisotropy, which has been used recently as as giant magnetoresistance medium. 12 However, contrary to the 200 nm period in the stripe domain system, which is of pure magnetic origin, the magnetic ordering period in our samples is morphologically defined, and dramatically reduced to 18 nm only.Our work is based on a previous experimental study of monolayer ͑ML͒ nanostripes of Fe͑110͒, prepared on vicinal W͑110͒ surfaces. 11 Their magnetic properties are dominated by a strong uniaxial magnetic anisotropy with an easy axis in the plane, but across the stripe axis, resulting in ferromagnetic interstripe coupling of magnetostatic origin, and in dipolar superferromagnetism. In the present letter, we focus on pseudomorphic Fe͑110͒ nanostripes prepared on vicinal W͑110͒ in the range between one and two pseudomorphic atomic layers ͑ALs͒. In this range, puzzling magnetic phenomena have been observed before for the case of films pre-pared on smooth W͑110͒, which consisted of DL islands in a ML sea. Frustration of remanent magnetic order in the center of this range, 13 explained in terms of a quasiantiferromagnetic interaction of unknown origin between DL islands, was alternatively interpreted in terms of magnetic freezing. 14,15 Only recently it could be shown that the origin of this frustration i...

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confidence: 99%

Perpendicular magnetization and dipolar antiferromagnetism in double layer nanostripe arrays of Fe(110) on W(110)

Hauschild

Gradmann

Elmers

1998

Applied Physics Letters

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“…The most basic one is the use of a polarizer that is rotated close to 90 • relative to the polarization of the beam. More advanced designs use photoelastic modulators 54 or Faraday modulators 55 to modulate the polarization of the light before it is passed through the analyzer. This generates a signal at the second harmonic of the modulation frequency that is proportional to the Kerr rotation and a signal at the modulation frequency that is proportional to the Kerr ellipticity.…”

Section: E Detectormentioning

confidence: 99%

A high-resolution combined scanning laser and widefield polarizing microscope for imaging at temperatures from 4 K to 300 K

Lange¹,

Guénon²,

Lever³

et al. 2017

Review of Scientific Instruments

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Polarized light microscopy, as a contrast-enhancing technique for optically anisotropic materials, is a method well suited for the investigation of a wide variety of effects in solid-state physics, as for example birefringence in crystals or the magneto-optical Kerr effect (MOKE). We present a microscopy setup that combines a widefield microscope and a confocal scanning laser microscope with polarization-sensitive detectors. By using a high numerical aperture objective, a spatial resolution of about 240 nm at a wavelength of 405 nm is achieved. The sample is mounted on a 4 He continuous flow cryostat providing a temperature range between 4 K and 300 K, and electromagnets are used to apply magnetic fields of up to 800 mT with variable in-plane orientation and 20 mT with out-of-plane orientation. Typical applications of the polarizing microscope are the imaging of the in-plane and out-of-plane magnetization via the longitudinal and polar MOKE, imaging of magnetic flux structures in superconductors covered with a magneto-optical indicator film via Faraday effect or imaging of structural features, such as twin-walls in tetragonal SrTiO 3 . The scanning laser microscope furthermore offers the possibility to gain local information on electric transport properties of a sample by detecting the beam-induced voltage change across a current-biased sample. This combination of magnetic, structural and electric imaging capabilities makes the microscope a viable tool for research in the fields of oxide electronics, spintronics, magnetism and superconductivity.

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“…using the Faraday modulator technique [6]. The measurements of Kerr hysteresis could be performed in a temperature range from room temperature up to 550 K. To perform the Kerr torque measurements the magnetic field with a maximum amplitude of Bmax = 2,3 T could be applied in any direction a by rotating the magnet.…”

Section: Introductionmentioning

confidence: 99%

Changes in Magnetic Anisotropy of Mo Films Induced by Nitrogen Diffusion From Protective Layers

et al. 1996

Self Cite

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-REtrM films used for magneto-optical (MO) data storage are commonly covered with reactively sputtered SiN protective layers. For stoichiometric Si3N4 cover layers no reaction between the magnetic and the protective layer is expected. But if there is a surplus of nitrogen within the protective layer the magnetic properties and the long-term stability of the magnetic layer may be influenced. To investigate this we prepared ferrimagnetic TbFeCo-films covered with a SiN protective layer containing a surplus of nitrogen. For testing their long-term stability the films were annealed several times. To analyze the magnetic properties measurements ofKerr hyst.eresis were performed. The magnetic anisotropy was measured by Kerr Torque Magnetometry, a very sensitive magneto-optical' method which provides local information about the anisotropy field at the surface region of the magnetic layer. As a result substantial changes of the magnetic properties at the surface region of the TbFeCo layers were detected. These changes were induced by a diffusion of nitrogen from the protective into the magnetic layer leading to a reduced content of magnetically active Tb at the surface. At longer annealing times this led in extreme to a double layer behaviour which makes the medium useless for MO data storage.

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A Kerr magnetometer using Faraday modulation technique

Cited by 16 publications

References 2 publications

Perpendicular magnetization and dipolar antiferromagnetism in double layer nanostripe arrays of Fe(110) on W(110)

Perpendicular magnetization and dipolar antiferromagnetism in double layer nanostripe arrays of Fe(110) on W(110)

A high-resolution combined scanning laser and widefield polarizing microscope for imaging at temperatures from 4 K to 300 K

Changes in Magnetic Anisotropy of Mo Films Induced by Nitrogen Diffusion From Protective Layers

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