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We report a new cancer imaging modality in the contrast of tissue intrinsic susceptibility property by computed inverse magnetic resonance imaging (CIMRI). In MRI physics, an MRI signal is formed from tissue magnetism source (primarily magnetic susceptibility χ) through a cascade of MRI-introduced transformations (e.g. dipole-convolved magnetization) involving MRI setting parameters (e.g. echo time). In two-step computational inverse mappings (from phase image to internal fieldmap to susceptibility source), we could remove the MRI transformations and imaging parameters, thereby obtaining χ-depicted cancer images (canχ) from MRI phase images. Canχ is computationally implemented from clinical cancer MRI phase image by CIMRI. As a result of MRI effect removal through computational inverse mappings, the reconstructed χ map (canχ) could provide a new cancerous tissue depiction in contrast of tissue intrinsic magnetism property (i.e. diamagnetism vs paramagnetism) as in an off-scanner state (e.g. in absence of main field B 0). Through retrospective clinical cancer MRI data analysis, we reported on the canχ method in technical details and demonstrated its feasibility of innovating cancer imaging in the contrast of tissue intrinsic paramagnetism/diamagnetism property (in a cancer tissue state free from MRI effect). [ABSTRACT FROM AUTHOR]

For one of the most famous and widely investigated intermediate-valence compound SmB6, we report the results of a precise experimental study of the pressure effect on magnetic susceptibility χ. The measurements of χ(P) were carried out under helium gas pressure P up to 2 kbar at fixed temperatures 78 and 300 K using a pendulum-type magnetometer. The observed pressure effect value, d lnχ/dP ∼ –6 Mbar–1, demonstrates a noticeable decrease in susceptibility under pressure, which is weakly dependent on temperature used. From model analysis of the experimental data, combined with the supplemented LSDA + U calculations of the electronic structure and van Vleck paramagnetism of the band states of SmB6, we have estimated the value of the initial pressure derivative for the intermediate valence of Sm. It is consistent with the literature data obtained by other methods and indicates an increase in valence with increasing pressure. It was shown that the valence of Sm and its pressure dependence are closely related to the detailed characteristics of the conduction band and 4f states. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the magnetic properties of mixed nanocrystalline Zn/manganese oxide compounds synthesized by a hydrothermal method. These compounds are designed as (ZnO)1−n(MnO)n, where index n ranges from 0.05 to 0.60. The results of magnetic measurements, including AC magnetic susceptibility as a function of temperature (up to 160 K) and frequency (from 7 Hz up to 9970 Hz), as well as DC magnetization in magnetic fields up to 9 T and temperature up to 50 K, are reported. We observed various types of magnetic behavior depending on the nominal weight content of MnO. Samples with a low nominal content (up to n = 0.10) of MnO exhibited Curie–Weiss behavior at higher temperatures. For samples with high nominal weight contribution (from n = 0.30 to 0.60), spin-glass-like or/and weak ferromagnetic behavior is observed. [ABSTRACT FROM AUTHOR]

The A3M2M'O6 type materials Na3Ca2BiO6 and Na3Ni2BiO6 were successfully synthesised through two sol-gel techniques - a method based on a natural deep eutectic solvent, and a biopolymer-mediated synthesis. The materials were analysed using Scanning Electron Microscopy to determine if there was a difference in final morphology between the two methods, and it was found that the natural deep eutectic solvent method resulted in a more porous morphology. For both materials, the optimum dwell temperature was found to be 800 °C, which in the case of Na3Ca2BiO6 was a much less energy-intensive synthesis process than its seminal solid-state synthesis. Magnetic susceptibility measurements were undertaken on both materials. It was found that Na3Ca2BiO6 exhibits only weak, temperature independent paramagnetism. Na3Ni2BiO6 was found to be antiferromagnetic, with a Néel temperature of 12 K, in line with previously reported results. [ABSTRACT FROM AUTHOR]

The A3M2M'O6 type materials Na3Ca2BiO6 and Na3Ni2BiO6 were successfully synthesised through two sol-gel techniques - a method based on a natural deep eutectic solvent, and a biopolymer-mediated synthesis. The materials were analysed using Scanning Electron Microscopy to determine if there was a difference in final morphology between the two methods, and it was found that the natural deep eutectic solvent method resulted in a more porous morphology. For both materials, the optimum dwell temperature was found to be 800 °C, which in the case of Na3Ca2BiO6 was a much less energy-intensive synthesis process than its seminal solid-state synthesis. Magnetic susceptibility measurements were undertaken on both materials. It was found that Na3Ca2BiO6 exhibits only weak, temperature independent paramagnetism. Na3Ni2BiO6 was found to be antiferromagnetic, with a Néel temperature of 12 K, in line with previously reported results. [ABSTRACT FROM AUTHOR]

Magnetic susceptibility measurements are often the first characterization tool that researchers turn to when beginning to assess the magnetic nature of a newly discovered material. Breakthroughs in instrumentation have made the collection of high quality magnetic susceptibility data more accessible than ever before. However, the analysis of susceptibility data remains a common challenge for newcomers to the field of magnetism. While a comprehensive treatment of the theoretical aspects of magnetism are found in numerous excellent textbooks, there is a gap at the point of practical application. We were inspired by this obstacle to put together this guide to the analysis and interpretation of magnetic susceptibility data, with an emphasis on materials that exhibit Curie-Weiss paramagnetism. Magnetic susceptibility measurements are an integral technique used across chemistry, physics and materials science; however, while straightforward to perform, interpretation of the data is often not. Here, the authors provide a basic guide to help newcomers interpret magnetic susceptibility data outlining examples based around the Curie-Weiss law that are ideal for those wishing to learn the basics of this method. [ABSTRACT FROM AUTHOR]

A very simple, but rich experiment, encompassing a classical Galileo’s pendulum, has been devised to be performed at home, especially during the Covid-19 pandemics. The experiment uses a miniature supermagnet rod as the pendulum oscillating element suspended from a fixed sewing thread. Its physics can be fully investigated, allowing to study the oscillation movements and to extract the gravity acceleration constant. The interaction with chemical substances can be accurately monitored by equilibrating the magnetic attraction of the probe as it opposes the gravity restoring force. Magnetic susceptibilities can be precisely measured in this way, allowing to access the number of unpaired electrons in the compounds, while stimulating discussions in the light of the ligand field theory. The simplicity and the opportunity of joining physics and chemistry are the most relevant aspects of the experiment. Curiously, the pendulum performance also implies a meditation like posture, requiring complete silence and confinement. In this sense it can also help relaxing our mind during the pandemics.

Dirac matters have attracted a lot of interest due to their unique band structure with linear band dispersions, which have great potential for technological applications. Recently, three-dimensional Dirac and Weyl semimetals have invoked distinctive phenomena originating from a non-trivial Berry phase. In this study, we prepare single crystals of TixZr1-xTe5 with a highly anisotropic Fermi surface. Our detailed electrical transport measurements reveal that the crystals show the Lifshitz transition, and Ti doping induces a band shift. Further quantum oscillation analyses demonstrate that the TixZr1-xTe5 crystals are 3D Dirac semimetals. Additionally, we observed a minimum temperature-dependent magnetic susceptibility, which is close to a peak position of electrical resistivity. This observation is interpreted in terms of the Berry paramagnetism. Our finding paves the way to determine a band topology by magnetism and also provides a platform to apply the Berry magnetism to Dirac semimetals. Topologically non-trivial materials demonstrate a range of exotic electronic phases related to the Berry phase of the system and recent investigations are also considering the magnetic properties in order to further enrich the physics of these materials. Here, the authors perform electronic transport and magnetization measurements on single crystals of Ti-doped ZrTe5 revealing them to be 3D Dirac semimetals that may also exhibit Berry paramagnetism. [ABSTRACT FROM AUTHOR]

Dirac matters have attracted a lot of interest due to their unique band structure with linear band dispersions, which have great potential for technological applications. Recently, three-dimensional Dirac and Weyl semimetals have invoked distinctive phenomena originating from a non-trivial Berry phase. In this study, we prepare single crystals of TixZr1-xTe5 with a highly anisotropic Fermi surface. Our detailed electrical transport measurements reveal that the crystals show the Lifshitz transition, and Ti doping induces a band shift. Further quantum oscillation analyses demonstrate that the TixZr1-xTe5 crystals are 3D Dirac semimetals. Additionally, we observed a minimum temperature-dependent magnetic susceptibility, which is close to a peak position of electrical resistivity. This observation is interpreted in terms of the Berry paramagnetism. Our finding paves the way to determine a band topology by magnetism and also provides a platform to apply the Berry magnetism to Dirac semimetals. Topologically non-trivial materials demonstrate a range of exotic electronic phases related to the Berry phase of the system and recent investigations are also considering the magnetic properties in order to further enrich the physics of these materials. Here, the authors perform electronic transport and magnetization measurements on single crystals of Ti-doped ZrTe5 revealing them to be 3D Dirac semimetals that may also exhibit Berry paramagnetism. [ABSTRACT FROM AUTHOR]

Magnetic fabric analyses of rocks by anisotropy of magnetic susceptibility (AMS) are a robust petrofabric tool that has been used in varied geological environments and tectonic settings. A fundamental difficulty of this method is to define the dominant magnetic phases and their resulting geological interpretation. We study the magnetic behavior of rocks by simulating data of mixed magnetic phases (i.e., diamagnetic, paramagnetic, and ferromagnetic). We show that it is possible to recognize the dominant magnetic phases by measuring the mean susceptibility at room temperature (kmRT) and at low temperature (kmLT). Distinct regions of magnetic phase dominancy are demonstrated in kmLT/kmRT versus kmRT and kmLT versus kmRT plots. We present a comprehensive approach by coupling the magnetic phase dominancy with possible magnetic fabrics, which are obtained from AMS measured at room and low temperatures (RT‐AMS and LT‐AMS) and anisotropy of anhysteretic remanent magnetization, into a scenario table. Application of this table allows a robust procedure for determining which magnetic phases are dominant, and permits a fast and reliable geological interpretation in complex settings. Key Points: We present a robust procedure for determining the anisotropy of magnetic susceptibility (AMS) carriers (ferro, para, and diamagnetic phases)Mean susceptibility at room and low temperatures defines the respective contributions of the magnetic phases to the rock's susceptibilityA novel scenario table, coupling respective contributions and associated magnetic fabrics, allows reliable interpretation of AMS data [ABSTRACT FROM AUTHOR]

While charge-ordering transition is well established in the oxygen-deficient layered cobaltite YBaCo2O5, there has been no evidence for the transition in the analogous compound GdBaCo2O5 either from neutron diffraction or from magnetic susceptibility experiments. In this paper, we present comparative studies on the electron spin resonance (ESR) of Gd3+ ions in Y1-xGdxBaCo2O5 (x = 0.01, 0.25, and 1) polycrystalline samples. Magnetic susceptibility was also performed for comparison with the ESR results. It was found that charge-ordering transition for Y0.75Gd0.25BaCo2O5 revealed by the susceptibility is also manifested in the characters of the ESR data. The similar temperature-evolution of the ESR parameters for GdBaCo2O5 provides a support for the existence of charge-ordering transition, although no characteristic of the transition is evidenced from susceptibility experiments, which can be understood as being hidden by dominant paramagnetism of Gd3+ ions in this compound. We have interpreted the temperature variation of ESR parameters in terms of electron localization associated with Co2+/Co3+ charge ordering. [ABSTRACT FROM AUTHOR]

We present an experimental and theoretical study of Pauli paramagnetism and martensite stabilization in a near equiatomic NiTi shape memory alloy. We demonstrate a direct correlation between strain-induced shear of the B19′ NiTi lattice and its electronic and thermodynamical features. An increase in the monoclinic angle β from 97.4 to 98° induces a 7% decrease in the magnetic susceptibility because of a shift and deepening of a dip in B19′ density of states at the Fermi level. It also produces a decrease in the B19′ enthalpy, which translates into an increase in the martensite-to-austenite transition temperature by 60 K. [ABSTRACT FROM AUTHOR]

Using canonical ensemble, we have studied the magnetic properties of a cylindrical GaAs quantum dot in this paper. The system is under the direct influence of external static electric and magnetic fields and an Aharonov-Bohm magnetic flux. Considering the temperature- and pressure-dependent effective parameters, the magnetic susceptibility is calculated and plotted in different regimes. Results clearly show the magnetic susceptibility, magnetic transition, and critical points strongly depend on temperature, pressure, and magnetic field. Moreover, Aharonov-Bohm magnetic flux has considerable effects on the magnetic susceptibility of the system. [ABSTRACT FROM AUTHOR]

Paramagnetic metal ions with fast-relaxing electrons generate pseudocontact shifts (PCSs), residual dipolar couplings (RDCs), paramagnetic relaxation enhancements (PREs) and cross-correlated relaxation (CCR) in the nuclear magnetic resonance (NMR) spectra of the molecules they bind to. These effects offer long-range structural information in molecules equipped with binding sites for such metal ions. Here we present the new open-source software Paramagpy, which has been written in Python 3 with a graphic user interface. Paramagpy combines the functionalities of different currently available programs to support the fitting of magnetic susceptibility tensors using PCS, RDC, PRE and CCR data and molecular coordinates in Protein Data Bank (PDB) format, including a convenient graphical user interface. Paramagpy uses efficient fitting algorithms to avoid local minima and supports corrections to back-calculated PCS and PRE data arising from cross-correlation effects with chemical shift tensors. [ABSTRACT FROM AUTHOR]

Magnetic particles have become a promising tool for nearly all major lab-on-a-chip (LOC) applications, from sample capturing, purification, enrichment, transport to detection. For biological applications, the use of magnetic particles is especially well established for immunomagnetic separation. There is a great amount of interest in the automation of cell sorting and counting with magnetic particles in LOC platforms. So far, despite great efforts, only few fully functional LOC devices have been described and further integration is necessary. In this review, we will describe the physics of magnetic cell sorting and counting in LOC formats with a special focus on recent progress in the field. [ABSTRACT FROM AUTHOR]

The structural, magnetic, and electric properties of Dy1-xSrxCoO3-δ perovskite have been investigated systematically over the range of doping, 0.65≤x≤0.90. The Rietveld refinements of x-ray powder diffraction patterns at room temperature indicate that the samples with 0.65≤x≤0.75 show a tetragonal structure with I4/mmm group symmetry, while the compounds with 0.80≤x≤0.90 are cubic with pm3m group symmetry. Zero field-cooled magnetization, M(T), of 0.65≤x≤0.85 samples reveals a cusp at around room temperature. For all samples, M(T) increases rapidly below 50 K due to the paramagnetism of Dy sublattice. The inverse magnetic susceptibility, χ-1(T), was described by using Curie–Weiss law. The resistivity (ρ) data can be explained according to a three-dimensional variable range hopping model in a certain temperature range. The density of states at the vicinity of Fermi level is roughly estimated. [ABSTRACT FROM AUTHOR]

The reversal time of the magnetization of a single-domain ferromagnetic particle with a cubic anisotropy in the presence of a uniform magnetic field is evaluated using the Kramers escape rate theory for intermediate-to-high damping as extended by Brown [W. F. Brown, Jr., IEEE Trans. Magn. 15, 1196 (1979)] to the analogous magnetic spin problem. It is shown that this formula is in complete agreement with the relaxation time calculated numerically from the solution of the stochastic Landau-Lifshitz-Gilbert equation describing the dynamics of the magnetization of the particles. It is also shown that knowledge of the reversal time τ allows one to predict accurately the spectrum of the longitudinal magnetic susceptibility in the low-frequency range. [ABSTRACT FROM AUTHOR]

TiO2 nanoparticles doped with 1%, 5%, and 10% M (M=Co, Fe, and Ni) were prepared by microwave irradiation and characterized using x-ray diffraction, transmission electron microscopy, and magnetometry. The as-prepared samples are found to be paramagnetic at room temperature, with the magnetic susceptibility following the Curie-Weiss law in the investigated range of 2–300 K. However, transformation from paramagnetism to room-temperature ferromagnetism (RTFM) was observed by hydrogenating the samples at 400 °C. Reheating in air converted the samples back to paramagnetic while rehydrogenating the samples again induced ferromagnetism. It is argued that the reversible RTFM observed is due to interaction between the dopant metal ions and oxygen vacancies produced during hydrogenation. X-ray diffraction of the hydrogenated Co- and Fe-doped samples shows only a single TiO2 phase suggesting that the observed RTFM may be intrinsic, but for the Ni-doped samples the magnetism may arise from metallic Ni on the surfaces of the TiO2 nanoparticles. [ABSTRACT FROM AUTHOR]

The magnetic susceptibility of undoped GaAs substrates is measured from 2 to 300 K. It comprises two types of temperature-dependent net-paramagnetic contributions. One is a Van Vleck-type paramagnetic contribution which scales inversely with the band gap of the semiconductor and thus increases up to room temperature. The other resembles a Langevin-type paramagnetism which sets in only at low temperatures after certain thermal cycling procedures. [ABSTRACT FROM AUTHOR]

The magnetic field and temperature dependence of the magnetic susceptibility is studied for the ferromagnetic layered manganites SrO(La[sub 1-x]Sr[sub x]MnO[sub 3])[sub 2] in the composition range x=0.32-0.40. In the paramagnetic phase, the susceptibility exhibits an anomalous maximum at an intermediate magnetic field value. The size of this field-induced susceptibility enhancement increases dramatically with x from 10% for x=0.32 to 160% for x=0.40. The temperature dependence of the effect shows a maximum at Tapprox. 1.1 T[sub C] for all x. Quantitative analysis in terms of the Landau theory of phase transitions enables us to identify a distortion of the free energy F in the paramagnetic phase that is associated with the susceptibility anomaly. This free energy distortion corresponds to a magnetic system that approaches a first order magnetic phase transition as the temperature is lowered toward T[sub C]. Such a behavior is indicative of a second, competing order param! eter, which is identified as the recently observed charge density wave. In the immediate vicinity of T[sub C], the anomaly disappears and the system seems to undergo a more conventional second order paramagnetic-ferromagnetic phase transition. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Low-temperature magnetic properties were investigated on the gold nano particles (GNPs) with an average size of 11.5 nm, assembled with molecules of ruthenium complex (Ru0), and phenylboronic acid (B0) by the proton nuclear magnetic resonance (1H-NMR) and susceptibility measurements. The temperature dependence of the NMR shift and the uniform susceptibility was described as the sum of the Curie–Weiss term and a positive constant term. From the former, the average number of Ru0 on each GNP was estimated to be 118, which is 23% of the calculation. The finite positive constant term shows a clear contrast with the well-known fact that the bulk gold is diamagnetic. Finally, a disappearance of the motional narrowing effect in the proton NMR spectra below 60 K indicates that the wavering motion of Ru0 complexes on GNP at room temperature is frozen at low temperatures. [ABSTRACT FROM AUTHOR]

Investigates the mutual influence of the atomic and magnetic ordering during the heating of the disordered equi-atomic CoPt alloy. Calculation of temperature dependence; Behavior of magnetic susceptibility in the paramagnetic region; Nature of the magnetization on the platinum atoms.

Nature of phase transition in polycrystalline LaVO3 has been studied using Mössbauer spectroscopy with 1% 57Fe doped sample. Magnetic susceptibility of sample taken upon both field cooled and zero-field cooled exhibited a peak at TN∼137 K, indicative of antiferromagnetic-paramagnetic phase transition. Up to 110 K, Mössbauer spectra were well-resolved sextets. However, abrupt first-order collapse in the hyperfine pattern took place in the narrow temperature range of 110–115 K, which is much below the transition temperature TN deduced from the magnetic measurement. Spectral lines became broader with increasing temperature until a pronounced central singlet appeared near 115 K, suggesting the appearance of relaxation effect. The first-order-like collapse in hyperfine magnetic spectra was found to originate from the fast relaxation due to dynamic magnetostrictive deformation setting in much below TN. [ABSTRACT FROM AUTHOR]

Nature of phase transition in polycrystalline LaVO3 has been studied using Mössbauer spectroscopy with 1% 57Fe doped sample. Magnetic susceptibility of sample taken upon both field cooled and zero-field cooled exhibited a peak at TN∼137 K, indicative of antiferromagnetic-paramagnetic phase transition. Up to 110 K, Mössbauer spectra were well-resolved sextets. However, abrupt first-order collapse in the hyperfine pattern took place in the narrow temperature range of 110–115 K, which is much below the transition temperature TN deduced from the magnetic measurement. Spectral lines became broader with increasing temperature until a pronounced central singlet appeared near 115 K, suggesting the appearance of relaxation effect. The first-order-like collapse in hyperfine magnetic spectra was found to originate from the fast relaxation due to dynamic magnetostrictive deformation setting in much below TN. [ABSTRACT FROM AUTHOR]

Mechanical (elastic) properties have been derived for polycristalline TiMn 2 from micro-indentation and thermal expansion measurements. With a room temperature (RT) Vicker's hardness of ∼11 GPa, TiMn 2 is a rather hard intermetallic material. The elastic modulus is E = 217 ± 4 GPa at RT. Physical properties (from 1.8 K to 300 K) including specific heat, electrical resistivity and magnetic susceptibility reveal temperature independent paramagnetism and metallic conductivity consistent with a Bloch-Grüneisen behavior. Based on experimental data (X-ray powder diffraction, metallography, SEM and EMPA on 30 alloys prepared by various methods employing arc melting, powder reaction sintering in closed crucibles as well as nitriding binary master alloys in 10 5  Pa nitrogen gas) phase relations in the ternary system Ti-Mn-N have been established and calculated for the isothermal section at 900 °C. The thermodynamic modelling relies on existing thermodynamic assessments of the Mn-N and Ti-N binary systems and on our recent modelling of the Ti-Mn system, which is characterized by a significantly higher thermodynamic stability of the C14-type Laves phase Ti 1-x Mn 2+x than hitherto assumed in the literature. It is this higher stability, which is consistent with the experimental phase triangulation in Ti-Mn-N: as the most important consequence of the higher stability of Ti 1-x Mn 2+x , compatibility exists between the only two congruently melting compounds Ti 1-x Mn 2+x and TiN 1-x . The high melting refractory solution TiN 1-x dominates the liquidus surface pushing all monovariant melting lines close to the Ti-Mn binary. [ABSTRACT FROM AUTHOR]

Two iron(II)-rhenium(IV) compounds of general formula [FeII(dmf)6][ReIVX6] [X = Cl (1) and Br (2); dmf = N,N-dimethylformamide] have been prepared and characterized. X-ray powder diffraction measurements on samples of 1 and 2 support the same structure for both systems. The crystal structure of 1 was determined by single-crystal X-ray diffraction. 1 crystallizes in the triclinic system with space group Pī. Each iron(II) is six-coordinate and bonded to six oxygens from six dmf molecules building a distorted octahedral environment. Rhenium(IV) is six-coordinate by six halide anions in an almost regular octahedral geometry. The magnetic properties were investigated from variable-temperature magnetic susceptibility measurements performed on microcrystalline samples of 1 and 2, whose experimental data were reproduced by a model of two isolated paramagnetic centers [S = 2 (FeII) and S = 3/2 (ReIV)] with large values of zero-field splitting (zfs) parameter. [ABSTRACT FROM AUTHOR]