Measurement of low temperatures in strong magnetic fields

Astrov, D. N.; Abilov, G. S.; Al'Shin, B. I.

doi:10.1007/bf01205105

Cited by 10 publications

(3 citation statements)

References 7 publications

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“…Smolensky and Ioffe [2] were the first to try said approach, nearly a half century ago, in the antiferromagneticferroelectric perovskite Pb(Fe 1/2 Nb 1/2 )O 3 (or PFN). Confirmation of a weak spontaneous magnetic moment in the ferroelectric phase below 9 K was later confirmed [3].…”

Section: Introductionmentioning

confidence: 66%

Recent advancements in magnetoelectric particulate and laminate composites

et al. 2007

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Recently, the magnetoelectric (ME) effectdielectric polarization of a material under magnetic field, or induced magnetization under an electric field-has become the focus of significant research interests. The primary requirement for the observance of said effect is the coexistence of magnetic and electric dipoles. Most of the known single phase materials suffer from the drawback that the ME effect is quite small, even at low temperatures limiting their applicability in practical devices. Better alternatives are ME composites, which have large magnitudes of the ME voltage coefficient. Composites exploit the product property of materials; where the ME effect is realized by combining magnetostrictive and piezoelectric phases that independently are not ME, but acting together (i.e., their product) result in a ME effect. In this review article, we survey recently reported results concerning ME composites, focusing on ME particulate (synthesized via a controlled precipitation technique) and laminated composites. The article also provides a survey of the compositions and magnitudes of the ME coefficients reported in the literature; a brief description of the analytical models developed to explain and predict the behavior of composites; and discuss several applications that are made possible by enhanced ME effects.

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Section: Introductionmentioning

confidence: 66%

Recent advancements in magnetoelectric particulate and laminate composites

et al. 2007

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“…The approach used in this Letter, specifically the combination of first-principles calculations for artificially imposed magnetic states with Monte Carlo simulations of magnetoelectric response at elevated temperatures, opens a route to theoretical studies of a large variety of temperature-dependent static and dynamic magnetoelectric phenomena. It applies to other materials with strong temperature variations of ME susceptibility, such as Fe 2 TeO 6 [29], ðGaFeÞO 3 [30], and Ti 2 O 3 [31], and can be extended to account for relativistic effects. Accurate predictions of the magnitude of magnetoelectric responses at finite temperature will greatly facilitate the search for and design of materials with the strongest responses.…”

mentioning

confidence: 99%

Temperature-Dependent Magnetoelectric Effect from First Principles

et al. 2010

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We show that nonrelativistic exchange interactions and spin fluctuations can give rise to a linear magnetoelectric effect in collinear antiferromagnets at elevated temperatures that can exceed relativistic magnetoelectric responses by more than 1 order of magnitude. We show how symmetry arguments, ab initio methods, and Monte Carlo simulations can be combined to calculate temperature-dependent magnetoelectric susceptibilities entirely from first principles. Introduction.-Recent years have seen a resurgence of interest in materials with coupled electric and magnetic dipoles motivated by the prospect of controlling spins with applied voltages and charges with applied magnetic fields in novel multifunctional devices. The simplest form of such a control is the linear magnetoelectric (ME) coupling between electric polarization and an applied magnetic field or, conversely, between magnetization and an applied electric field. Although the linear ME effect was theoretically predicted and experimentally discovered more than 50 years ago [1], finding technologically useful materials displaying strong ME coupling at room temperature remains a challenging problem [2].Recent progress in the related field of multiferroic materials, in which ferroelectric polarizations are induced by noncentrosymmetric magnetic orderings, has led to a clarification of the microscopic origins for ME coupling [3]. In particular, two distinct coupling mechanisms have been identified. The first arises from relativistic effects linking electron spin and orbital momentum, resulting in the antisymmetric S 1 Â S 2 interaction between spins of different magnetic ions. The strength of this Dzyaloshinksii-Moriya interaction depends on polar displacements of ions, which can make magnets with noncollinear spiral orders becoming ferroelectric [4][5][6][7]. In the second mechanism, polar deformations of the lattice are induced by Heisenberg spin exchange interactions S 1 Á S 2 , originating from the Fermi statistics of electrons [8,9]. This nonrelativistic mechanism can give rise to stronger spin-lattice couplings than those resulting from relativistic effects, which tend to be relatively weak in 3D transition metal compounds. Indeed, in multiferroics, the electric polarizations induced by exchange interactions in Y 1Àx Lu x MnO 3 and GdFeO 3 exceed the largest polarizations observed in spiral multiferroics by 1 order of magnitude [10,11]. It was recently suggested that Heisenberg exchange can also give rise to a relatively strong linear ME effect [12] which, however, seemed to require rather special noncollinear spin orderings and crystal structures, making it difficult to find such materials in nature.

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“…Effects were well described and reported in industrial applications, cryogenics and thermophysical property measurements in the cryogenic temperature range below the triple point of water [1][2][3] and in above 100 • C temperature applications [1,[4][5][6]. Numerous papers reported measuring errors of thermometers of different types (magnetic: resistance thermometers, thermocouples and thermistors, and non-magnetic: vapour pressure and gas thermometers) while subject to high dc magnetic fields (up to 19 T) at low temperatures (below 40 K) [7][8][9][10]. Within thermocouple temperature measurements, Seebeck coefficients were reported to be strongly dependent on the magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Magnetic effects on thermocouples

Beguš¹,

Bojkovski²,

Drnovšek³

et al. 2014

Meas. Sci. Technol.

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Thermometers in laboratory environment and industrial applications are often subject to extraneous, usually unwanted and uncontrolled magnetic fields. Magnetic field influence can be minimized, but cannot be fully cancelled out. Even more, in most cases, there is no awareness of the existence of magnetic fields, let alone their effect on measurement instrumentation. In the past, sensitivity to high dc magnetic fields has been investigated in cryogenics and at high temperatures. More recently, the magnetic effect on weak dc magnetic fields was presented. The goal of this paper was to analyse and empirically and experimentally prove the magnetic sensitivity of thermocouples exposed to low magnetic fields: both dc and ac. Precision and uniform alternating and direct magnetic flux densities were generated by means of permanent magnets and power amplifiers with air-cored coils. The magnetic effect on ferromagnetic and non-ferromagnetic thermocouples at liquid-nitrogen-boiling point (−196 °C), ice point (0 °C), in water (17 °C) and at melting point of gallium fixed point cell (29.7646 °C) was investigated. Magnetic-field-dependent temperature errors of up to 700 mK (at 5.3 mT: dc) and up to 1 °C (at 10 mT: ac 50 Hz magnetic fields) were detected. From the results, it can be concluded that, ideally for temperature measurements of the highest accuracy in the above-cryogenic temperature range, magnetic sensitivity should be estimated and taken into account either as the correction of an error and/or as an additional source of measurement uncertainty. Special consideration should be given to thermocouple orientation relative to the magnetic field direction, influence of metal enclosures and magnetization effects on ferromagnetic components of thermocouples.

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Measurement of low temperatures in strong magnetic fields

Cited by 10 publications

References 7 publications

Recent advancements in magnetoelectric particulate and laminate composites

Recent advancements in magnetoelectric particulate and laminate composites

Temperature-Dependent Magnetoelectric Effect from First Principles

Magnetic effects on thermocouples

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