A simple AC susceptometer mounted on a cryostat cold finger

Dumelow, T.; Xavier, M. M.; Cabral, Fernando A.; Chesman, C.

doi:10.1016/s0304-8853(00)00824-6

Cited by 4 publications

(3 citation statements)

References 3 publications

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“…We named the signal obtained by the PMR signal. Equations ( 2), ( 5), and (6) show that the PMR signal depends on the product of the second derivative of the magnetic energy with respect to the equilibrium position of the magnetization times the first derivative of the resistance with respect to the equilibrium position of the magnetization. A parameter sensitive to the 2nd derivative is, for instance, the switching field of the magnetization that is defined as the point of instability close to the saturation state.…”

Section: Discussionmentioning

confidence: 99%

“…Measurements of the magnetic properties of nanostructures are usually performed by means of a variety of techniques which depending on the type of the external excitation and the time scale of response can be considered as static, quasi-static, or dynamic techniques. 1,2 The basic principles on which the experimental techniques are created rely on different magnetic phenomena, such as magnetic induction, [3][4][5][6] magnetic force, 7,8 magneto-optical properties, [9][10][11] magnetic resonances, [12][13][14][15] light scattering by magnetic excitations, 16 and magnetoresistance. 17,18 To be suitable for investigation of magnetic properties of nanostructures, the development of new techniques has to consider two key aspects: (i) being able to measure weak signals and (ii) providing information on magnetic phenomena that are not easily obtained by wellestablished techniques.…”

Section: Introductionmentioning

confidence: 99%

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Perturbative measurement of magnetoresistance

Oliveira

Melo

Costa

et al. 2018

Review of Scientific Instruments

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In this paper, we report the development of a novel technique in which the magnetoresistance of nanostructures is perturbatively measured by transversally modulating the DC magnetic field. It measures the electrical transport counterpart of the transverse magnetic AC-susceptibility. The technique was developed in a conventional four-probe configuration in which a small DC current flows through the sample and a small transverse AC-field perturbates the equilibrium position of the sample magnetization. Lock-in detection, in-phase with the AC-perturbation, is used to measure the voltage signal between the two inner electrodes of the four-probe station. We successfully demonstrated that this signal is proportional to the product of the first derivative of sample resistance with respect to the equilibrium position of the magnetization times the second derivative of the energy with respect to the equilibrium position of the magnetization. These dependences add new features to the technique investigated here that were not captured by the investigations previously reported on the same subject. To show the effective use of the technique, we discuss its application in measuring magnetic properties of thin magnetic films in the non-saturated regime.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Perturbative measurement of magnetoresistance

Oliveira

Melo

Costa

et al. 2018

Review of Scientific Instruments

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show abstract

“…In other cases (including the biomedical field of interest) the temperature is not an adjustable parameter, and the optimal frequency and amplitude are the only quantities to be determined. Commercial susceptometers are available (often coupled with cryogenic systems and thus rather expensive) and home-made setups are reported in the literature 8,9 . Home-made setups offer the advantage of adapting the sensor volume to the sample size.…”

Section: Introductionmentioning

confidence: 99%

A room-temperature alternating current susceptometer—Data analysis, calibration, and test

Alderighi

Bevilacqua

Biancalana

et al. 2013

Review of Scientific Instruments

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An AC susceptometer operating in the range of 10 Hz to 100 kHz and at room temperature is designed, built, calibrated, and used to characterize the magnetic behaviour of coated magnetic nanoparticles. Other weakly magnetic materials (in amounts of some millilitres) can be analyzed as well. The setup makes use of a digital acquisition system in order to determine the amplitude and the phase of the sample magnetization as a function of the frequency of the driving magnetic field, which is powered by a digital waveform generator. A specific acquisition strategy makes the response directly proportional to the sample susceptibility, taking advantage of the differential nature of the coil assembly. A calibration method based on conductive samples is developed.

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A DSP-enhanced AC susceptometer for characterisation of superconductors

Babet

Jarvis

2013

2013 Africon

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A simple AC susceptometer mounted on a cryostat cold finger

Cited by 4 publications

References 3 publications

Perturbative measurement of magnetoresistance

Perturbative measurement of magnetoresistance

A room-temperature alternating current susceptometer—Data analysis, calibration, and test

A DSP-enhanced AC susceptometer for characterisation of superconductors

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