Many interesting properties of polynomials are closely related to the geometry of their Newton polytopes. We analyze the coercivity on R of multivariate polynomials f ∈ R[x] in terms of their Newton polytopes. In fact, we introduce the broad class of so-called gem regular polynomials and characterize their coercivity via conditions imposed on the vertex set of their Newton polytopes. These cond...

It was observed that the coercivity of CoCrPt films deposited on a polyimide tape was much lower than the coercivity deposited on a rigid glass substrate under identical conditions. X-ray diffraction showed that the desirable ~112! and ~110! texture of the NiAl/CrMn underlayers on the tape substrate was severely degraded during the deposition process. This resulted in the destruction of ~10.0! ...

Local coercivity variation of Co/Pd nanomultilayers has been investigated by measuring the polar Kerr hysteresis loops of the local areas of submicron size using a magneto-optic Kerr microscope system. Interestingly, the local coercivity distribution was very sensitive to an increase in the number of repeats: the ~2 Å Co/11 Å Pd)10 sample showed a smooth variation of the local coercivity, while...

The effects of Nd2Fe14B grain size and Nd coating on the coercivity in sputter-deposited Nd-Fe-B/Nd thin films have been investigated in order to gain an insight into the coercivity mechanism of Nd-Fe-B magnets. Highly textured Nd2Fe14B particles were grown successfully on the MgO(100) single-crystal substrate with the Mo underlayer. As the Nd-Fe-B layer thickness t NFB was decreased from 70 to...

Structural and magnetic properties of laminated sNd,DydsFe,Co,Nb,Bd5.5 /Fe nanocomposites are investigated. Normally, the addition of the soft phase to the hard phase enhances the remanence but deteriorates the permanent-magnet performance of the material by reducing the coercivity. In the present system, the coercivity increases to 1608 kA/m s20.2 kOed in thermally processed Nd–Dy–Fe–Co–Nb–Bs1...

Influence of replacing Sr ions by rare-earth ions (RE) ions on the structural and magnetic properties of high coercivity (Hc) SrFe10Al2O19 hexaferrite have been investigated using X-ray diffraction, transmission electron microscopy, differential scanning calorimeter, and SQUID. A 73% increase in intrinsic coercivity is observed for Al doped SrFe10Al2O19 as compared to that of pure SrFe12O19. Th...

For Co and CoNi single layer films, the coercivity is a linear function of the inverse layer thickness and has an angular dependence of a fourfold-like symmetry although only a uniaxial anisotropy exists. For both as-prepared and post field-cooled Co/FeMn bilayers, the exchange field and the coercivity enhancement are proportional to the inverse Co thickness. For as-prepared ones, the exchange ...

The local coercivity distribution of CoCrPt alloy films prepared by dc magnetron sputtering has been investigated by means of magneto-optical microscope magnetometer, capable of simultaneously measuring the local magnetic properties on a submicrometer spatial resolution. We find that with increasing Pt concentration the local coercivity distribution becomes asymmetric and the average local coer...

The high coercivity of 26.2 kOe for SmCo5 nanoflakes are obtained by multistep (three steps) surfactant-assisted ball milling. The magnetic properties, phase structure and morphology are studied by VSM, XRD and SEM, respectively. The results demonstrate that the three step ball-milling can keep more complete crystallinity (relatively less defects) during the process of milling compared with one...

The present paper is dedicated to the numerical solution of stationary free boundary problem by means of shape optimization. We assume that the state satisfies the Dirichlet problem and track the Neumann data at the free boundary. The gradient and Hessian of the shape functional under consideration are computed. By analysing the shape Hessian in case of matching data a sufficient criterion for ...