We consider a mean-field continuum model of classical particles in Rd with Ising or Heisenberg spins. The interaction has two ingredients, a ferromagnetic spin coupling and a spin-independent molecular force. We show that a feedback between these forces gives rise to a first-order phase transition with simultaneous jumps of particle density and magnetization per particle, either at the threshol...

We present results of an electron paramagnetic resonance (EPR) study of Nd1−xSrxMnO3 with x = 0.5 across the paramagnetic to ferromagnetic, insulator to metal transition at 260 K (Tc) and the antiferromagnetic, charge ordering transition (TN = Tco) at 150 K. The results are compared with those on Nd0.45Sr0.55MnO3 which undergoes a transition to a homogeneous A-type antiferromagnetic phase at TN...

The chiral spin-glass Potts system with q=3 states is studied in d=2 and 3 spatial dimensions by renormalization-group theory and the global phase diagrams are calculated in temperature, chirality concentration p, and chirality-breaking concentration c, with determination of phase chaos and phase-boundary chaos. In d=3, the system has ferromagnetic, left-chiral, right-chiral, chiral spin-glass,...

This paper presents a warm bore ferromagnetic shimming design for a high resolution NMR magnet based on spherical harmonic coefficient reduction techniques. The passive ferromagnetic shimming along with the active shimming is a critically important step to improve magnetic field homogeneity for an NMR Magnet. Here, the technique is applied to an NMR magnet already designed and built at the MIT'...

We give a complete characterization of the two-state anti-ferromagnetic spin systems whichare of strong spatial mixing on general graphs. We show that a two-state anti-ferromagneticspin system is of strong spatial mixing on all graphs of maximum degree at most ∆ if and onlyif the system has a unique Gibbs measure on infinite regular trees of degree up to ∆, where∆ can be either ...

in this work firstly fe2o3 nanoparticles were synthesized via a simple chemical method. properties of the product were examined by x-ray diffraction pattern (xrd), scanning electron microscope (sem) and fourier transform infrared (ft-ir) spectroscopy. vibrating sample magnetometer (vsm) shows nanoparticles exhibit ferromagnetic behavior. to continue some of the 2-naphthol condensed 1,3-oxazinon...

The effect of magnetic fluctuations on the critical behaviour of unconventional ferromagnetic superconductors (UGe2, URhGe, etc.) and superfluids is investigated by the renormalization-group method. For the case of isotropic ferromagnetic order a new unusual critical behaviour is predicted. It is also shown that the uniaxial and bi-axial magnetic symmetries produce fluctuation driven phase tran...

We studied the dilute substitution effect on magnetic and transport properties in an unstable ferromagnet CeFe2 with a C15 cubic Laves-phase structure. In the Co substitution system Ce(Fe12xCox)2 with x<0.10, while the Curie temperature TC decreases with increasing the Co concentration, an antiferromagnetic ordering appears in the low temperature region for x^0.05, and the transition temperatur...

Critical current in multifilamentary Ag-sheath Bi-2223 tape is enhanced to some extent by means of thin and narrow coating of pure nickel. The concept of enhancing critical current is based on the magnetic shielding effect resulting in redirection of self-field flux lines. The Ni coating was introduced at the edge regime of the tape in order to redirect the perpendicular component of self-field...