Soft-magnetic materials characterized using a superconducting solenoid as magnetic source

Mastrogiacomo, Giovanni; Löffler, Jörg F.; Dilley, N. R.

doi:10.1063/1.2838733

Cited by 9 publications

(8 citation statements)

References 19 publications

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“…It should be noted that in a superconducting coil trapped magnetic flux may lead to deviations of reported and real magnetic field. Especially, when measuring the magnetization, magnetoresistance, or the Hall resistivity of a soft ferromagnet in a field sweep through zero, the reversal of the hysteresis (i.e., of the coercive fields) may be observed [37]. The presented data were measured in an MPMS3 magnetometer with a 7-T magnet and a PPMS with a 9-T magnet, respectively.…”

Section: Methodsmentioning

confidence: 99%

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Detection of antiskyrmions by topological Hall effect in Heusler compounds

Kumar

Reehuis

et al. 2020

Phys. Rev. B

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Heusler compounds having D2d crystal symmetry gained much attention recently due to the stabilization of a vortex-like spin texture called antiskyrmions in thin lamellae of Mn1.4Pt0.9Pd0.1Sn as reported in the work of Nayak et al. [Nature 548, 561 (2017)]. Here we show that bulk Mn1.4Pt0.9Pd0.1Sn undergoes a spin-reorientation transition from a collinear ferromagnetic to a non-collinear configuration of Mn moments below 135 K, which is accompanied by the emergence of a topological Hall effect. We tune the topological Hall effect in Pd and Rh substituted Mn1.4PtSn Heusler compounds by changing the intrinsic magnetic properties and spin textures. A unique feature of the present system is the observation of a zerofield topological Hall resistivity with a sign change which indicates the robust formation of antiskyrmions. I. INTRODUCTIONTopological magnetic textures show promise in many areas of technology, such as racetrack memory [1,2] and neuromorphic computing [3,4], due to the unique transport properties that allow for efficient manipulation [5,6] and detection [7,8] of the magnetic textures. This is a consequence of the real space Berry curvature of the topological texture that can be tuned by the electronic structure [9,10]. One such topological texture is the skyrmion [11,12] which is found in chiral magnets [13] with a unit integer topological charge.Recently antiskyrmions (aSKs) [14], the anti-particles of the skyrmions, were stabilized in thin lamellae of the tetragonal inverse Heusler compound Mn1.4Pt0.9Pd0.1Sn for a broader field range and even above room temperature [15]. In this compound (D2d symmetry class), the Dzyaloshinskii-Moriya interaction (DMI) is anisotropic where the DM vectors along the x and y directions in the basal plane are of opposite sign and hence cause the stability of the aSKs [16]. The in-plane winding of the spin texture for an aSK is anisotropic with an opposite topological charge as compared to that of the azimuthally symmetric Bloch and Néel skyrmion of the same charge [17]. The topological winding induces a real space Berry curvature that strongly influences all transport properties [18]. The topological Hall effect (THE) is one such electrical transport property that has been intrinsically linked to the skyrmions [8]. The THE results in a further component of the total Hall signal, in addition to the normal Hall and the magnetization-scaled anomalous Hall components [19]. It arises due to the emergent magnetic field which is a result of the finite Berry phase contributions from either II. EXPERIMENT Polycrystalline ingots of Mn1.4Pt1-xPdxSn (x = 0, 0.1 … 0.3) and Mn1.4Pt1-yRhySn (y = 0.1, 0.2 … 0.8) with the stoichiometric amounts of constituent elements were prepared by arcmelting in the presence of Ar atmosphere. The synthesized ingots were sealed in an evacuated quartz tube and annealed at 873 K (Pd-substituted samples) and 1073 K (parent compound Mn1.4PtSn and Rh-substituted samples) for 7 days followed by quenching into an ice-water mixture. The phase purity and the cryst...

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Section: Methodsmentioning

confidence: 99%

“…The presented data were measured in an MPMS3 magnetometer with a 7-T magnet and a PPMS with a 9-T magnet, respectively. In field sweeps both systems typically produce a maximum field error of 20 Oe around zero field [37].…”

Section: Methodsmentioning

confidence: 99%

Detection of antiskyrmions by topological Hall effect in Heusler compounds

Kumar

Reehuis

et al. 2020

Phys. Rev. B

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“…To take into account the remanent field due to trapped flux in the superconducting magnet coils, it was necessary to measure a standard paramagnetic Dy 2 O 3 pellet which exhibits no hysteresis. 30 This was done at T = 300 K in the field range of H = ±16 T with the same field step size and procedure used in measuring the RAF sample. The difference in field between the same magnetization values when ramping up and down in field was fitted to a Voigt line shape and the result was used to adjust the actual value of the magnetic field.…”

Section: Magnetometrymentioning

confidence: 99%

Interfacial coupling between ferromagnets and random and dilute antiferromagnets

et al. 2011

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Depth profiles for pinned and unpinned magnetizations were determined across the interface between a ferromagnet (F) and random and dilute antiferromagnets (RAF and DAF) exemplified by Fe0.45Ni0.55F2/Co and Fe0.34Zn0.66F2/Co bilayers, respectively, using polarized neutron reflectivity (PNR). PNR measurements were complemented by magnetometry using applied fields as large as 160 kOe to assure saturation of the entire sample, including magnetic moments that are normally pinned at lower fields. The locations of pinned and unpinned magnetization in the ferro-and antiferromagnets were identified. The origin of exchange bias in the RAF system is noticeably different than that of the DAF system. In the RAF system, a domain wall is formed at the RAF/F interface when the ferromagnet's magnetization is reversed. In the DAF system, some domains within the bulk of the DAF are reversed upon reversal of the ferromagnet while others remain pinned. In this case, the interface magnetization is entirely reversed.

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“…Where the magnetic fields are concerned, it has to be noted that the "stealthy" properties of C-CSH also lead to much smaller errors of m caused by the trapped field of the superconducting magnet [19,20,[52][53][54]. They are also reduced 20 to 30 times, from a level of about +4 × 10 −7 emu when the specimen is housed in a single capsule to the magnetometer noise level of 10 −8 emu in C-CSH.…”

Section: Discussion: Validation and An Example Of The True Potentialmentioning

confidence: 99%

In Situ Compensation Method for Precise Integral SQUID Magnetometry of Miniscule Biological, Chemical, and Powder Specimens Requiring the Use of Capsules

Gas

Sawicki

2022

Materials

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Steadily growing interest in magnetic characterization of organic compounds for therapeutic purposes or of other irregularly shaped specimens calls for refinements of experimental methodology to satisfy experimental challenges. Encapsulation in capsules remains the method of choice, but its applicability in precise magnetometry is limited. This is particularly true for minute specimens in the single milligram range as they are outweighed by the capsules and are subject to large alignment errors. We present here a completely new experimental methodology that permits 30-fold in situ reduction of the signal of capsules by substantially restoring the symmetry of the sample holder that is otherwise broken by the presence of the capsule. In practical terms it means that the standard 30 mg capsule is seen by the magnetometer as approximately a 1 mg object, effectively opening the window for precise magnetometry of single milligram specimens. The method is shown to work down to 1.8 K and in the whole range of the magnetic fields. The method is demonstrated and validated using the reciprocal space option of MPMS-SQUID magnetometers; however, it can be easily incorporated in any magnetometer that can accommodate straw sample holders (i.e., the VSM-SQUID). Importantly, the improved sensitivity is accomplished relying only on the standard accessories and data reduction method provided by the SQUID manufacturer, eliminating the need for elaborate raw data manipulations.

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Soft-magnetic materials characterized using a superconducting solenoid as magnetic source

Cited by 9 publications

References 19 publications

Detection of antiskyrmions by topological Hall effect in Heusler compounds

Detection of antiskyrmions by topological Hall effect in Heusler compounds

Interfacial coupling between ferromagnets and random and dilute antiferromagnets

In Situ Compensation Method for Precise Integral SQUID Magnetometry of Miniscule Biological, Chemical, and Powder Specimens Requiring the Use of Capsules

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