Results of thermal analysis performed at different heating rates on eight glasses of the As-Sb-Se system, with compositions represented by (As, Sb) 40 Se 60 and As x Sb 15 Se 85 − x are reported and discussed. The values of the glass transition temperature ( T g ), the crystallisation temperature ( T c ) and the peak temperature of crystallisation ( T p ) are found to be independent of particle size. From the heating rate dependence of T g and T p values of the activation energy for glass transition ( E t ) and the activation energy for crystallisation ( E c ) are evaluated and their composition dependence discussed. The crystallisation data are examined in terms of recent analyses developed for non-isothermal crystallisation studies to arrive at E c and details of the crystallisation mechanism. The results indicate bulk nucleation and crystallisation with two and three dimensional growth respectively for the As x Sb 15 Se 85 − x and (As, Sb) 40 Se 60 glasses.

Calorimetric measurements on as-sb-se glasses

There are provided a magnetoresistance effect element, a magnetic head, a magnetic head assembly and a magnetic recording system, which have high sensitivity and high reliability. The magnetoresistance effect element has two ferromagnetic layers, a non-magnetic layer provided between the ferromagnetic layers, and a layer containing an oxide or nitride as a principal component, wherein the layer containing the oxide or nitride as the principal component contains a magnetic transition metal element which does not bond to oxygen and nitrogen and which is at least one of Co, Fe and Ni.

Magnetoresistance effect element

Magnetic properties of Co/Pd and Co/Pt multilayers were studied as a function of sputtering gas pressure. It was found that the magnetic properties of the films depended upon the sputtering gas pressure, and large coercivity (several kOe) and a perfect squareness of the perpendicular hysteresis loop were attained by the deposition at the high gas pressure. These multilayers are suitable for perpendicular magnetic recording media. In the Co/Pd, the origin of the perpendicular magnetic anisotropy is mainly an interfacial anisotropy, although there exists a stress‐induced anisotropy for the films with the relatively short periodicity. The perpendicular magnetic anisotropy of the Co/Pt can be concerned with the Co‐Pt mixture formed at the interface of the multilayer structure. The magnetostriction of the Co/Pd films with the relatively short periodicity is extraordinarily large with a negative sign, since Co atoms adjacent to Pd atoms at the interface could induce larger magnetostriction than that of pure Co....

Perpendicular magnetic anisotropy and magnetostriction of sputtered Co/Pd and Co/Pt multilayered films

Co1−xPtx alloys with Pt contents in the range 0.45≤x≤0.9 show sizable perpendicular magnetic anisotropy, 100% perpendicular remanence and coercivities in the range 160 kA/m. Thin films of this material are grown by electron beam evaporation onto fused silica or Si, at substrate temperatures between 150 and 350 °C. Spectroscopic investigations of the polar Kerr rotation show a significant enhancement of the Pt related UV peak. A comparison of the static signal levels R×(θk2+ek2)1/2 of Co/Pt multilayers and alloys shows an overall 50% enhancement in the case of alloys. Curie temperatures around 200 °C are observed for Co∼22Pt∼78 compositions. These properties, together with the potentially high chemical stability and ease of manufacturing make Co1−xPtx alloys very attractive materials for short wavelength magneto‐optic recording.

Magnetic and magneto‐optical properties of cobalt‐platinum alloys with perpendicular magnetic anisotropy

An atomic layer deposited dielectric layer and a method of fabricating such a dielectric layer produce a reliable dielectric layer having an equivalent oxide thickness thinner than attainable using SiO2. Depositing a hafnium metal layer on a substrate surface by atomic layer deposition and depositing a hafnium oxide layer on the hafnium metal layer by atomic layer deposition form a hafnium oxide dielectric layer substantially free of silicon oxide. Dielectric layers containing atomic layer deposited hafnium oxide are thermodynamically stable such that the hafnium oxide will have minimal reactions with a silicon substrate or other structures during processing.

Electronic apparatus with deposited dielectric layers

The magnetostriction constant and saturation magnetization at room temperature are measured for iron‐based amorphous alloys containing various kinds of metalloid and metal atoms, except Co and Ni. The data show that the magnetostriction constant is proportional to the square of the saturation magnetization for these alloys.

Magnetostriction and magnetization of iron-based amorphous alloys

Magnetic properties of CoPd alloy films prepared by rf magnetron sputtering were studied as a function of the Pd content. CoPd alloy films showed extraordinarily large magnetostriction the order of 10-4 in a Pd-rich composition, and it was found that the perpendicular magnetic anisotropy was related to the magnetostrictive effect. The CoPd alloy films can be considered to be perpendicular magnetic recording material.

Perpendicular Magnetic Anisotropy in Sputtered CoPd Alloy Films

Co/Pd and Co/Pt multilayer films were prepared by magnetron-type sputtering and their magnetic properties were characterized by a polar Kerr loop tracer. Both multilayer films had perpendicular magnetic anisotropy when the Co layer became 10 A. It was found that the magneto-optical and magnetic properties were significantly affected by the film thickness. The Kerr rotation angle θk was enhanced at the film thickness t\lesssim500 A and the Kerr remanence to saturation ratio became θkr/θk=1 at t200 A. In the Co/Pd system, the coercive force was influenced by the sputtering gas pressure. Simultaneous enhancement in θk and θkr/θk is assumed to originate from the different natures.

https://iopscience.iop.org/article/10.1143/JJAP.28.L659/pdf

Magneto-Optical Properties in Ultrathin Co/Pd and Co/Pt Multilayer Films

From the temperature dependence of the hole concentration p(T) in a lightly Al-doped 4H-SiC epilayer, an Al acceptor with ∼200 meV and an unknown defect with ∼370 meV are found. By irradiation with 4.6 MeV electrons, the Al acceptor density is reduced, while the unknown defect density is almost unchanged. This indicates that the substitutional Al atoms in 4H-SiC are displaced by irradiation or that the bonds between the substitutional Al atom and the nearest neighbor atom are broken by irradiation. Moreover, the reduction in p(T) with irradiation arises from the decrease of the Al acceptors, not from the formation of hole traps or donor-like defects.

/pdf/decrease-in-al-acceptor-density-in-al-doped-4h-sic-by-12c7vbxvlx.pdf

Decrease in Al acceptor density in Al-doped 4H-SiC by irradiation with 4.6 MeV electrons

An amorphous magnetic alloy consists of 2 to 20 at % (atomic percent) of ruthenium atoms; 10 to 30 at % of atoms of at least one amorphous forming element selected from the group consisting of phosphorus, carbon, silicon, boron and germanium; and iron atoms as the predominant component of the balance.

Koichi Aso

Papers

Magnetostriction and magnetization of iron-based amorphous alloys

Perpendicular Magnetic Anisotropy in Sputtered CoPd Alloy Films

Magneto-Optical Properties in Ultrathin Co/Pd and Co/Pt Multilayer Films

Decrease in Al acceptor density in Al-doped 4H-SiC by irradiation with 4.6 MeV electrons

Amorphous magnetic alloy