Susceptibility and Inverted Hysteresis Loop of Prussian Blue Analogs with Orthorhombic Structure

The magnetic susceptibility of ternary metal Prussian blue analogues with orthorhombic structure is studied using Ising model. Within the frame work of effective-field theory with correlations, the roles of the mole fraction y, uniaxial magnetic anisotropy, transverse and longitudinal magnetic field are discussed in details. The temperature dependence of the magnetic susceptibility is also investigated. The interesting phenomenon of the inverted magnetic hysteresis loop has been found. The results can help to understand the experimental work of the molecule-based ferriferrimagnet.     

巨正则量子Monte Carlo方法和二维Hubbard模型的研究

用巨正则量子Monte Carlo方法,计算了二维单带Hubbard模型的局域磁矩、磁化率、交错磁化率和内能等物理量.结果表明,用巨正则量子Monte Carlo方法能够统一地研究Hubbard模型的关联强度从弱至强区域的性质,它是处理强关联多体系统的有效方法.     

Klassische Berechnung der magnetischen Suszeptibilität und der magnetischen Abschirmung der Kerne diamagnetischer Moleküle

Calculation of Magnetic Susceptibility and Magnetic Shieldin g of the Nuclei of Diamagnetic Molecules In the present work we show that the general equations for a calculation of magnetic susceptibility and magnetic shielding of the nuclei of a diamagnetic molecule based on the work of REBANE [2] are identical with the formulae derived from the classical equations of motion of the electron density of the molecule [3]. Further more it is proved that the method does not depend on the choice of coordinate origin. Conditions for an incrementary calculation of magnetic susceptibility and shielding of nuclei are formulated and applied to results given in paper [1].     

Nonlinear 2D spin susceptibility in a finite magnetic field: spin-polarization dependence

By theoretically calculating the interacting spin susceptibility of a two-dimensional electron system in the presence of finite spin polarization, we show that the extensively employed technique of measuring the 2D spin susceptibility by linear extrapolation to a zero field from the finite-field experimental data is theoretically unjustified due to the strong nonlinear magnetic field dependence of the interacting susceptibility. Our work compellingly establishes that much of the prevailing interpretation of the 2D susceptibility measurements is incorrect, and, in general, the 2D interacting susceptibility cannot be extracted from the critical magnetic field for full spin polarization, as is routinely done experimentally.     

Physical properties of the β-Ti6Sn5 system

The current work reports the specific heat, the resistivity and the magnetic susceptibility of both single-crystal and polycrystalline β-Ti₆Sn₅ at cryogenic temperatures. The effects of small additions of magnetic and non-magnetic impurities were examined. Resistivity and magnetic susceptibility measurements reveal that the undoped material is a Pauli paramagnet displaying Fermi-liquid behaviour, while ferromagnetic ordering was observed at T150K with small additions of Ce, La or Co. Analysis of the electronic specific heat γ and magnetic susceptibility gives an unexpectedly large Wilson ratio R _w of 1.76, a value indicative of correlated electron behaviour. We present the general physical properties and based on the sensitivity of the magnetic properties to doping, show evidence that β-Ti₆Sn₅ exhibits a ground state in close proximity to a non-magnetic and magnetic phase boundary.     

Third-Order Magnetic Susceptibility of an Ideal Fermi Gas

At low temperature and under weak magnetic field, non-interacting Fermi gases reveal both Pauli paramagnetism and Landau diamagnetism, and the magnitude of the diamagnetic susceptibility is 1/3 of that of the paramagnetic one. When the temperature is finite and the magnetic field is also finite, we demonstrate that the paramagnetism and diamagnetism start to deviate from the ratio 1/3. For understanding the magnetic properties of an ideal Fermi gas at quite low temperature and under quite weak magnetic field, we work out explicitly the third-order magnetic susceptibility in three cases, from intrinsic spin, orbital motion and in total. An interesting property is in third-order magnetic susceptibilities:when viewing individually, they are both diamagnetic, but in total it is paramagnetic.     

Spin–lattice relaxation phenomena in the magnetic state of a suggested Weyl semimetal CeAlGe

ABSTRACT

In this work, we report the results of DC susceptibility, AC susceptibility and related technique, resistivity, transverse and longitudinal magnetoresistance and heat capacity on polycrystalline magnetic semimetal CeAlGe. This compound undergoes antiferromagnetic type ordering around 5.2 K (T¹). Under the application of external magnetic fields, parallel alignment of magnetic moments is favoured above 0.5?T. At low field and temperature, frequency and AC field amplitude response of AC susceptibility indicate the presence of spin–lattice relaxation phenomena. The observation of spin–lattice interaction suggests the presence of the Rashba–Dresselhaus spin–orbit interaction which is associated with inversion and time-reversal symmetry breaking. Additionally, the presence of negative and asymmetric longitudinal magnetoresistance indicates anomalous velocity contribution to the magnetoresistance due to the Rashba–Dresselhaus spin–orbit interaction which is further studied by heat capacity.     

Supporting theory of a new magnetic separator and classifier. Equations and modeling: Part I – Non-magnetic particles

Conventional magnetic separators are only able to split the feeding stream into three different outcome streams. This work presents the theoretical principles of a new device, named MAGCLA™, which is capable to separate and classify particles according to their magnetic susceptibility. This first part of the work reports the equations of movement for non-magnetic particles. The equations for magnetic particles and the limiting conditions for both situations will be given in the remaining parts of this work.A coefficient (T_CG1) was introduced to measure the deviations between the experimental and theoretical values.     

Physico-chemical parameters of alkali halides using optical electronegativity

A relation between optical electronegativities and some physico-chemical parameters of alkali halides are proposed. The estimated refractive index, optical susceptibility, electronic polarizability, magnetic susceptibility, heat of atomization, bond energy, ionization potential, plasma energy and lattice energy values are in good agreement with the values cited in the literature. The proposed equations are simple and have the advantage over others that less computational work is involved in the calculations of physico-chemical parameters of alkali halides.     

Magnetic susceptibility of quark matter within Fermi-liquid theory

Possibility of spontaneous magnetization in QCD and magnetic properties of quark matter are discussed by evaluating the magnetic susceptibility within Fermi-liquid theory. The screening effects for gluons are taken into account to figure out the specific properties of the magnetic transition in gauge theories. It is shown that the static screening effect in terms of the Debye mass does not necessarily work against the magnetic instability; it promotes the instability, depending on the coupling constant and the number of flavors.     

Magnetic properties of DyNi<Subscript>2</Subscript>B<Subscript>2</Subscript>C studied with a two-ion model for antiferromagnets

In a rare-earth antiferromagnet, two neighboring magnetic ions order spontaneously in opposite directions below the Néel temperature. Especially when it is placed in an external magnetic field, the two magnetic ions react to the field in different ways, so that they usually have different magnitudes and orientations below the magnetic transition temperature. Therefore, to describe the magnetic structure of an antiferromagnet, the single-ion ferromagnetic-like model is inadequate. To solve this problem, a two-ion model for rare-earth antiferromagnets is proposed and used in this work to investigate the magnetic properties of DyNi₂B₂C. The magnetic susceptibility curves obtained with this model show good agreements with experimental data.     

The Physical Property of Susceptibility for One-Dimensional Ferrimagnetic Chain with Alternating Spins 1 and 1/2 in Finite Magnetic Field

We further calculate the dependence of χT on T in high magnetic fields,where χ denotes susceptibility and T is temperature,using our previous research work - Green function's decoupling approximate approach,for the one-dimensional ferrimagnetic chain with alternating spins 1 and 1/2.We find a linear correlation in certain range of magnetic field between the temperature of χT maximum and the magnetic field.Moreover,we simply analyze its physical meaning by our approach.     

The temperature dependence of some thermodynamical quantities of ferromagnetic alloys in the region of magnetic phase transition

This paper deals with the behaviour of ferromagnetic alloys in the region of magnetic phase transition. The temperature dependences of spontaneous magnetization, magnetic susceptibility and specific heat are discused. The theoretical results are compared with experimental data.I wish to thank Professor L.Valenta for his kind guidance and advice given to me during my work on this paper.     

Electronic properties of metallic small particles

The electronic properties of very small metallic particles are reviewed. The emphasis is placed on the experimental work done by the author's group using nuclear magnetic resonance. The anomalies in the properties such as the spin susceptibility and the nuclear spin lattice relaxation arising from the discreteness of the orbital energies are discussed. For superconducting particles, the fluctuation of the order parameter and the critical magnetic field are also discussed.     

Ferromagnetism of Electron Gas

We here investigate the density and temperature dependence of polarization using the relativistic formalism for the electron–electron interaction within the Fermi liquid model. The variational method has been used: the free energy has been minimized with respect to the effective mass and the polarization parameter. Then we obtained the equation of state and magnetic susceptibility of the system. The exact results for polarization and magnetic susceptibility have been obtained at zero temperature. It has been shown that for a given temperature (density) there is a critical density (temperature) at which the ferromagnetic phase can appear in an electron gas. The results are in agreement with previous work. Our results show that at nonzero temperatures and in very low and very high densities the ferromagnetism phase cannot exist.     

Magnetization and magnetic susceptibility of InAs nano-rings

In this work, we investigate theoretically the magnetic susceptibility of the three-dimensional cut-torus-shaped quantum rings. The calculations are carried out for the realistic three-dimensional model of InAs/GaAs nano-rings with the hard-wall confinement potential, three-dimensional effective one-electronic-band Hamiltonian with position and energy-dependent effective mass, and Ben Daniel–Duke boundary conditions. This allows us to describe the penetration of the magnetic field into the torus region. At zero temperature, the ring's differential susceptibility demonstrates delta-like paramagnetic peaks, which are generated by aperiodic oscillations of magnetization. With increasing temperature, the peaks gradually transform into Lorenz-shaped peaks and then disappear. As opposed to meso-scopic quantum rings we found a dependence of the peak's amplitude on the dimensions of the rings.     

Independency of Fe ions in hemoglobin on immunomagnetic reduction assay

Immunomagnetic reduction (IMR), which involves measuring the reduction in the ac magnetic susceptibility of magnetic reagents, is due to the association between bio-functionalized magnetic nanoparticles and target bio-molecules. This has been demonstrated for assaying proteins in solutions free of Fe ions, such as serum. In this work, the validity of IMR assay for samples rich in Fe ions like hemoglobin (Hb) is investigated. According to the results, there is no magnetic signal contributed by Fe-ion-rich Hb. Furthermore, the results show a high sensitivity in assaying hemoglobin A1c (HbA1c) by using IMR.     

Critical behaviour of the local magnetic susceptibility in a ferromagnetic film

The nearest-neighbour Ising model of a ferromagnetic film in which couplings between surface spins may differ from couplings between remaining spins is considered. Using the mean-field approximation, the local magnetic susceptibility defined as the derivative of the local magnetization with respect to the external uniform magnetic field is obtained. The behaviour of the local magnetic susceptibility near the ordinary, surface-bulk and surface phase transitions and in a range of temperatures where physical quantities have pseudocritical behaviour is discussed. The critical behaviour of the local magnetic susceptibility in a three-dimensional semi-infinite model is also given for comparison.     

Magnetic equation of state for thin films

The magnetization fluctuations are considered in thin films treated as a set of monoatomic layers parallel to the film surfaces. The correlation functions have been determined and their forms are discussed. The influence of inhomogeneity of magnetization on the equation of state for a magnetic system described by Valenta's model is studied. The behaviour of the spontaneous magnetization as well as the magnetic susceptibility near the Curie point is described.This work is partially supported by the Institute of Physics of the P.A.S.     

Correlations between microstructure and a.c. magnetic response of bulk superconducting YBa2Cu3O7−x

Summary The magnetic response of granular superconducting YBCO samples with different grain sizes is reported. The analysis is carried out by measuring the low-frequency a.c. magnetic susceptibility as a function of the temperature with an applied magnetic field of amplitude ranging between 0.4 and 800 A/m. The observed magnetic behaviour is interpreted in terms of grain size and weak-links properties. The experimental results evidence the influence of the sample microstructure on the magnetic susceptibility. The intergranular and intragranular onset temperatures are compared with the critical temperature of the samples obtained by means of electrical-resistivity measurements. The temperature dependence of the intergranular critical current density is derived from the susceptibility data.