Фазовый состав и магнитная структура нанокомпозитов FeCoZr—(PbSrNaBi)(ZrTi)O₃

Изучены фазовый состав и магнитные свойства гранулированных нанокомпозитов FeCoZr—(PbSrNaBi)(ZrTi)O₃, синтезированных в кислородсодержащей среде с различным давлением кислорода. Анализ фазового состава выполнялся методами рамановской и ЯГР-спектроскопии, а магнитных свойств – методом вибрационной магнитометрии. Установлена взаимосвязь между условиями синтеза композитов, а также окислением металлических гранул, с одной стороны, и магнитными свойствами нанокомпозитов, с другой. Обнаружена возможность изменения положения порога перколяции и величины магниторезистивного эффекта в материале путём вариации давления кислорода при синтезе.Вивчено фазовий склад та магнетні властивості ґранульованих нанокомпозитів FeCoZr—(PbSrNaBi)(ZrTi)O₃, синтезованих у кисневмісному середовищі з різним тиском кисню. Аналіза фазового складу виконувалася методою Раманової та ЯГР-спектроскопії, а магнетних властивостей – методою вібраційної магнетометрії. Встановлено взаємозв’язок між умовами синтези композитів, а також окисненням металевих ґрануль, з одного боку, та магнетними властивостями нанокомпозитів, з іншого. Виявлено можливість зміни положення порогу перколяції та величини магнеторезистивного ефекту в матеріялі шляхом варіяції тиску кисню при синтезі.Phase composition and magnetic properties of FeCoZr—(PbSrNaBi)(ZrTi)O₃ granular nanocomposites synthesized in oxygen-containing ambient with different values of oxygen pressure are studied by Mössbauer spectroscopy, Raman spectroscopy, and vibrating sample magnetometry. Correlations between the synthesis conditions and oxidation of metallic granules and the magnetic properties of nanocomposites are determined. Possibility to tailor percolation threshold and modify magnetoresistive effect value in a material by varying oxygen pressure in a chamber during synthesis is revealed

Lattice anisotropy in uranium ternary compounds: UTX

Several U-based intermetallic compounds (UCoGe, UNiGe with the TiNiSi structure type and UNiAl with the ZrNiAl structure type) and their hydrides were studied from the point of view of compressibility and thermal expansion. Confronted with existing data for the compounds with the ZrNiAl structure type a common pattern emerges. The direction of the U-U bonds with participation of the 5f states is distinctly the "soft" crystallographic direction, exhibiting also the highest coefficient of linear thermal expansion. The finding leads to an apparent paradox: the closer the U atoms are together in a particular direction the better they can be additionally compressed together by applied hydrostatic pressure. (C) 2012 Elsevier B. V. All rights reserved

Multi-phase nature of sintered vs. arc-melted CrxAlFeCoNi high entropy alloys - experimental and theoretical study

High entropy CrxAlFeCoNi alloys with x = 0, 0.5, 1.0 and 1.5 were synthesized using arc-melting and sintering preparation techniques. Three crystal structures (fcc, bcc and σ) were observed using XRD technique, while EDX measurements showed the presence of up to three chemically different phases (FeCr-rich phase with fcc structure, AlNi-rich phase with bcc structure and Cr-rich phase with bcc and/or σ structures). The reasons for the observed phase coexistence were addressed to total energy electronic structure calculations using KKR-CPA method accounting for chemical disorder effects. Such theoretical analysis confirmed that the multi-phase system was energetically more favorable than the single-phase one. Furthermore, DSC measurements allowed to identify two phase transitions in melted samples, unlike sintered ones due to high-temperature nitrogen corrosion. This process turned out to be highly selective, resulting in the formation of the scales consisting of AlnNm–phases at the cost of total Al loss in the HEA alloy

Spin-Dependent Electronic Transport in IrMn–Co/Pd Multilayered Systems

Relation between magnetoresistance and magnetization reversal in thin multilayered IrMn-Co/Pd films deposited both on planar and nanoporous substrates is in focus of the present work. Magnetic anisotropy, exchange coupling and mechanisms of magnetic resistivity are discussed

Donor KIR B Genotype Improves Progression-Free Survival of Non-Hodgkin Lymphoma Patients Receiving Unrelated Donor Transplantation

Donor killer immunoglobulin-like receptor (KIR) genotypes are associated with relapse protection and survival after allotransplantation for acute myelogenous leukemia. We examined the possibility of a similar effect in a cohort of 614 non-Hodgkin lymphoma (NHL) patients receiving unrelated donor (URD) T cell-replete marrow or peripheral blood grafts. Sixty-four percent (n = 396) of donor-recipient pairs were 10/10 allele HLA matched and 26% were 9/10 allele matched. Seventy percent of donors had KIR B/x genotype; the others had KIR A/A genotype. NHL patients receiving 10/10 HLA-matched URD grafts with KIR B/x donors experienced significantly lower relapse at 5 years (26%; 95% confidence interval [CI], 21% to 32% versus 37%; 95% CI, 27% to 46%; P = .05) compared with KIR A/A donors, resulting in improved 5-year progression-free survival (PFS) (35%; 95% CI, 26% to 44% versus 22%; 95% CI, 11% to 35%; P = .007). In multivariate analysis, use of KIR B/x donors was associated with significantly reduced relapse risk (relative risk [RR], .63, P = .02) and improved PFS (RR, .71, P = .008). The relapse protection afforded by KIR B/x donors was not observed in HLA-mismatched transplantations and was not specific to any particular KIR-B gene. Selecting 10/10 HLA-matched and KIR B/x donors should benefit patients with NHL receiving URD allogeneic transplantation