We propose a very long baseline atom interferometer test of Einstein's equivalence principle (EEP) with ytterbium and rubidium extending over 10 m of free fall. In view of existing parametrizations ...of EEP violations, this choice of test masses significantly broadens the scope of atom interferometric EEP tests with respect to other performed or proposed tests by comparing two elements with high atomic numbfers. In the first step, our experimental scheme will allow us to reach an accuracy in the Eötvös ratio of 7 10−13. This achievement will constrain violation scenarios beyond our present knowledge and will represent an important milestone for exploring a variety of schemes for further improvements of the tests as outlined in the paper. We will discuss the technical realisation in the new infrastructure of the Hanover Institute of Technology (HITec) and give a short overview of the requirements needed to reach this accuracy. The experiment will demonstrate a variety of techniques, which will be employed in future tests of EEP, high-accuracy gravimetry and gravity gradiometry. It includes operation of a force-sensitive atom interferometer with an alkaline earth-like element in free fall, beam splitting over macroscopic distances and novel source concepts.
The mixed-valence manganite has sparked immense interest owing to its intriguing colossal magnetoresistance (CMR) effect. However, a research gap exists in the current literature regarding Nd-based ...manganites with intermediate bandwidth. This paper addresses this gap by investigating Nd0.7Sr0.3MnO3 (NSMO) ceramics prepared through two different synthesis approaches: the newly developed thermal treatment method (TT) and the well-established sol-gel method (SG). The XRD analysis revealed a single high-purity NSMO phase with insignificant alteration in Mn-O bond length and Mn-O-Mn bond angle for both samples. Nevertheless, SG exhibited larger particle size (209.3 nm) and better crystallinity in comparison to TT (178.6 nm). These factors significantly affect the magnetic transition width while preserving the Curie temperature, TC ≈ 246 K. Regarding electrical behaviour, TT showed a robust suppression of the metal-insulator transition temperature, TMI from 224 K (SG) to 182 K. This difference can be attributed to the existence of magnetic disordered layer at the grain boundaries. Consequently, this resulted in an increased scattering process and elevated resistivity from 8 Ω (SG) to 22 Ω (TT). Various theoretical models were employed to elucidate the transport mechanism at different temperature ranges. Interestingly, both samples displayed distinct magneto-transport behaviour despite negligible differences in their structural parameters. The occurrence of magnetoresistance peak in SG suggests a pronounced intrinsic CMR effect, while its absence in TT implies a dominant influence of extrinsic CMR. These findings highlight that the physical properties of the manganite are not only governed by their intragrain properties (TC) but are also influenced by intergrain contributions (TMI) when various synthesis routes were utilised.
•NSMO were prepared using novel thermal treatment and conventional sol-gel method.•Crystal structure remained unchanged, but crystallite size variation is significant.•The samples show distinct MR behaviours as different synthesis routes were applied.•Physical properties are affected by intragrain (TC) and intergrain (TMI) contributions.
In this work, a series of zinc- and manganese-co-doped magnetite nanoparticles was synthesized by co-precipitation method and their magnetization and magnetic hyperthermia properties were evaluated ...according to the degree of doping. The syntheses of the magnetic nanoparticles were carried out in the presence of polyethyleneglycol (PEG) at 353 K using aqueous medium. Several samples was synthesized with nominal composition of (ZnxMn1-xFe0.6)Fe2O4, x = (0–0.4). All samples were characterized by XRD and pure spinel structure like was observed, having about 13 nm diameter and truncated octahedral morphology. The magnetometry measures showed that the Zn and/or Mn additions in the magnetite structure contributed to enhance of the saturation magnetization as expected with the highest value of saturation magnetization for Zn-Mn equivalent doped magnetite. The magnetic hyperthermia properties were evaluated in aqueous media at pH 5 for 10 min in a 25 mT and 112 kHz alternating magnetic field and it was observed that manganese-only doped sample reached the highest hyperthermia rate, while Zn doping decreased hyperthermia property. The intrinsic loss power (ILP) values varies from 0.2 to 1.0 nHm2 kg−1 with Mn doping values increasing and the magnetic hyperthermia effect was assigned mainly to the Néel-Brownian relaxation process.
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•Co-precipitation led to nanoparticles with controlled sizes and morphologies.•Magnetization (Ms) increases with co-doping; high Zn levels lowers Ms values.•Magnetic hyperthermia increases with manganese doping levels.•Magnetic hyperthermia is mainly due to Néel-Brownian relaxation processes.
An increased focus on magnetic measurements of oriented single crystals, thin films, and magnetically dilute systems has led to a demand for the measurement of weak magnetic moments. This level of ...sensitivity and precision can be achieved on SQUID magnetometers by decreasing the size of the detection coils. However, the smaller detection coils can amplify two errors in the magnitude of the measured moment, the sample shape and radial offset effects, which were small and typically unaccounted for on previous magnetometers. We report a simple method to determine the radial offset of a sample by taking advantage of the two basic scan modes, DC and lock-in, typically used on magnetometers. This technique allows for the correction of the sample shape and radial offset effects in order to obtain the true moment of a sample. To show the efficacy of this technique, we report the magnetic properties of Ln2O3 (Ln=Gd, Dy, Er).
Correction for the sample shape and radial offset effects on SQUID magnetometers using a combination of DC and VSM scan data. Display omitted
•Sample shape and radial offset effects alter the moment measured by magnetometers.•We present a simple method to correct for these sample effects on magnetometers.•We measure magnetic susceptibilities of Ln2O3 to show the efficacy of this method.
Microwave spin resonance behaviour of Sr2+ doped Zirconium ferrite Zr1-xSrxFe2O4; (0 ≤ x ≥ 0.20) nanoparticles synthesized by auto combustion route has been investigated by electron paramagnetic ...resonance (EPR) which show a broad ferromagnetic resonance signal with a superimposed hump signal which is attributed to ferrite Fe3+ ions and oxygen vacancies which is in agreement with XRD and XPS. EPR shows low spin concentration and smaller relaxation time for Zr0.80Sr0.20Fe2O4 which can be used for hyperthermia and for use as a MRI contrast agent. EDS and XPS confirms the presence of Zr, Sr, Fe, O, and C and HRTEM images confirm growth along (220) and (311) with an interatomic distance of 0.3327 nm and 0.2622 nm respectively, thus, authenticating the formation of spinel structure in agreement with FTIR studies. The magnetic behaviour (M − H loop) shows high saturation magnetization and higher value of effective magnetocrystalline anisotropy (Keff) for Zr0.80Sr0.20Fe2O4.
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•Design of Double focusing stigmatic analyzer magnet.•Non-magnetic cavity based Homogenous magnet design.•Compensating coil based Homogenous magnet design.•Simple magnetic measurement bench design ...for bending magnets.
An electromagnetic Isotope Separator (EMIS) is used for separating isotopes by magnetic dispersion method. A dipole-bending magnet performs the fundamental function of separation and is an essential building block of EMIS. Unlike mass spectrometers and ion implantation systems, the EMIS prefers ribbon beams for effective mass separation and collection. The bending magnet described in this paper has an inbuilt hexapole and a tunable quadrupole doublet. This magnet separates the charged particles based on the mass-to-charge ratio, performs chromatic correction, and focuses the beam in both axes. All sector magnets focus the beam in the radial direction, the introduction of edge angle results in the vertical focusing of the beam at the expense of radial focusing. The exit pole of the magnet is rotatable for adjusting the focal point. The entry pole is curved for ensuring stigmatism correction in the beam and works like a hexapole. High magnetic field homogeneity is a key requirement for this magnet. This enhances the mass resolution. As per beam simulations, magnetic field non-homogeneity shall not exceed 200 ppm in good field region (GFR) of 200 mm (radial) and 60 mm(vertical). The paper discusses the design, production, installation, testing, and commissioning of a double-focusing Stigmator dipole magnet. A method for achieving low non-homogeneity by using non-magnetic cavities and compensation coils is described and implemented. Very high homogeneity magnets can be designed using this technique. The paper also describes an efficient method for the Magnetic qualification of bending magnets. Based on the design, a double-focusing stigmatic dipole magnet is produced, characterized, and installed.
Fault diagnosis has been considered as a crucial technique that the commercial fuel cell systems should be equipped with. Knowing that different faults or functioning modes can cause different ...distributions of current densities, monitoring the current density for fuel cells could be a possible solution to realize fault diagnosis. In the previous studies, a non-intrusive current density estimation method has been developed by measuring the magnetic fields around the fuel cells. However, a clear quantitative diagnosis strategy was not provided in these studies. This paper is dedicated to study a quantitative data-driven diagnosis strategy based on the magnetic measurement. In the proposed strategy, fault diagnosis can be realized by a two-step procedure, i.e., feature extraction and classification. The high diagnosis performance on the detection and identification of several common faults highlights the effectiveness of the proposed strategy. In addition to the basic diagnosis function, an index is proposed to quantify the faulty level as a fault is diagnosed. The proposed strategy is also compared with the ones in the literature to show its pros and cons.
This is first report on Nd-NbZn co-substituted M-type Ca-Sr hexaferrites with nominal compositions Ca0.4Sr0.6-xNdxFe12.0-x(Nb0.5Zn0.5)xO19 (x = 0.00–0.32) fabricated by the conventional solid-state ...reaction method. X-ray diffractometer (XRD), Fourier transformer infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), physical property measurement system-vibrating sample magnetometer (PPMS-VSM) were employed to characterize M-type calcium-strontium hexaferrites. XRD patterns of the hexaferrites with Nd-NbZn content (x) of 0.00 ≤ x ≤ 0.16 showed the single M-type hexaferrite phase. However, for the hexaferrites with Nd-NbZn content (x) ≥ 0.24, the impurity phase (α-Fe2O3) was observed. FT-IR frequency bands in the range (592–613) cm−1 and (430–470) cm−1 corresponded to the formation of tetrahedral and octahedral clusters of metal oxides in the hexaferrites, respectively. FE-SEM micrographs showed that the grains were platelet-like shapes. The saturation magnetization (Ms) and magneton number (nB) decreased with increasing Nd-NbZn content (x) from 0.00 to 0.32. The remanent magnetization (Mr) first increased with Nd-NbZn content (x) from 0.00 to 0.08, and then decreased when Nd-NbZn content (x) ≥ 0.08. The Mr/Ms ratio, coercivity (Hc) and magnetic anisotropy field (Ha) increased with increasing Nd-NbZn content (x) from 0.00 to 0.32. First anisotropy constant (K1) first slightly increased with Nd-NbZn content (x) from 0.00 to 0.08, and then decreased when Nd-NbZn content (x) ≥ 0.08.
•First report of studies on Nd-NbZn co-substituted M-type Ca-Sr hexaferrites.•Studied the effects of Nd-NbZn content (x) on the formation of M-type hexaferrite phase.•Magnetic measurements show a significant improvement in coercivity (Hc).•Established an optimum Nd-NbZn co-substitution content to obtain single phase M-type hexaferrites.
Magnesium ferrite (MgFe2O4) was synthesized using the solution combustion method. The concentration of the fuel was varied and investigated its effect on spectroscopic, structural and magnetic ...properties of MgFe2O4 nanoparticles. The XRD pattern showed a decrease in the crystallite size and increase in the lattice strain, dislocation density and specific surface area upon increasing the fuel amount. The shift in the FTIR band (~434 cm–1) corresponds to the Fe–O vibration in the octahedral sites. The values of HC decreased while Mr values increased continuously with the increase of the fuel concentration. The Mössbauer spectra of MgFe2O4 nanoparticles measured with a high velocity resolution demonstrated a large number of magnetic sextets assigned to the tetrahedral (A) and octahedral B sites. These magnetic sextets were considered as a result of different Fe3+ local microenvironments depending on Mg2+ cations distributions among the neighboring (A) and B sites. The calculations of binomial distribution of the probabilities of the numbers of Mg2+ cations within the sphere of 3.7 Å around Fe3+ cations in both (A) and B sites demonstrated distributions of different probabilities for these sites in agreement with the Mössbauer spectra fits. The numbers of magnetic sextets and their hyperfine parameters assigned to the (A) and B sites were found slightly varied for MgFe2O4 nanoparticles prepared with different fuel concentrations.
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•The values of HC decreased while Mr values increase with fuel concentration increase.•The Mössbauer spectra demonstrate many sextets assigned to both (A) and B sites.•The different numbers of Mg2+ around Fe3+ in both (A) and B sites were calculated.
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