55 Mn NMR experiments have been performed at 4.2 K on a series of Mn5(Ge1-xSix)3 5 (Ge 1- x Si x ) 3 epitaxial films (0 0 x 0.55) . 55 ) to investigate changes introduced by silicon when it replaces germanium in a hexagonal Mn5Ge3 5 Ge 3 crystal lattice. The Si/Ge substitution was found to reduce the magnetic moment on manganese located in the 6(g) sublattice creating a new population of manganese atoms with distinctly lower magnetic moment. This effect is attributed to the orbital overlay due to a lattice distortion introduced by Si. Interestingly, these modified Mn sites retain the orbital moment practically unaltered. The amount of new manganese environments in the 6(g) sublattice coincides with a probability of Mn having two Si neighbors as first neighbors. Mn atoms located in the 4(d) sublattice are not significantly affected by the Si substitution in the studied concentration range.

55Mn NMR experiments have been performed at 4.2 K on a series of Mn5(Ge1−xSix)3 epitaxial films (0⩽x⩽0.55) to investigate changes introduced by silicon when it replaces germanium in a hexagonal Mn5Ge3 crystal lattice. The Si/Ge substitution was found to reduce the magnetic moment on manganese located in the 6 g sublattice creating a new population of manganese atoms with distinctly lower magnetic moment. This effect is attributed to the modified exchange interactions due to a lattice distortion introduced by Si. Interestingly, these modified Mn sites retain the orbital moment practically unaltered. The amount of new manganese environments in the 6 g sublattice coincides with a probability of Mn having two Si neighbors as first neighbors. Mn atoms located in the 4d sublattice are not significantly affected by the Si substitution in the studied concentration range.

55Mn NMR experiments have been performed at 4.2 K on a series of Mn5(Ge1−xSix)3 epitaxial films (0⩽x⩽0.55) to investigate changes introduced by silicon when it replaces germanium in a hexagonal Mn5Ge3 crystal lattice. The Si/Ge substitution was found to reduce the magnetic moment on manganese located in the 6 g sublattice creating a new population of manganese atoms with distinctly lower magnetic moment. This effect is attributed to the modified exchange interactions due to a lattice distortion introduced by Si. Interestingly, these modified Mn sites retain the orbital moment practically unaltered. The amount of new manganese environments in the 6 g sublattice coincides with a probability of Mn having two Si neighbors as first neighbors. Mn atoms located in the 4d sublattice are not significantly affected by the Si substitution in the studied concentration range.

Nanolaminated Mn2GaC epitaxial films crystallizing in the hexagonal structure belong to the family of MAX phase compounds and display complex magnetic interactions. While the critical temperature of the order-disorder transition is 507 K, at around 214 K this compound undergoes a first-order phase transition with the magnetic structure below the transition point not being fully resolved. Previous studies indicated a noncollinear spin arrangement, but a specific magnetic structure could not be defined. In this work we present the results of 69Ga, 71Ga, and 55Mn NMR experiments performed at 4.2 K in an external in-plane magnetic field up to 1 T. The in-depth analysis of the experimental results shows a helical magnetic structure consisting of the ferromagnetically coupled Mn-C-Mn slabs that are twisted across the Ga layer by 167.2 degrees with respect to the next Mn-C-Mn slab. As a result, the magnetic structure presents a spiral propagating along the out-of-plane direction (hexagonal c axis) with a pitch of around 14 lattice constants.

Exposing sensors to environment without any physical protection introduces risk of failure due to collision with small hard objects like stones. This type of interaction is tested during product validation by usage of gravel bombardment procedures, originally designed for evaluating resistance of surface coating to chipping by gravel impact. While useful for practitioners, this procedure is difficult to be used during product design and virtual validation since it does not provide statistical measures regarding gravel size, mass or velocity distribution of moving gravels. Consequently, computer simulation must assume certain properties of impactors. The following simulation methodology evaluates risks associated with gravel bombardment test. It is based on impact force transmission through interconnects belonging to big and/or critical electronic components.

Zero-field NMR investigations on the 69Ga, 71Ga, and 55Mn nuclei have been performed at 4.2 K on a 100 nm thick epitaxial Mn2GaC(0001) MAX phase film grown on a MgO(111) substrate. This nano-laminated structure consists of ferromagnetic Mn-C-Mn stacks interleaved with monolayers of gallium. A resolved quadrupolar structure of the observed gallium resonances is a fingerprint of a well-defined crystal field confirming high crystal quality. The nuclei of non-magnetic gallium atoms are shown to experience the transferred hyperfine magnetic field of 15.75 T (& PLUSMN;0.05 T), which is due to polarization of their 4s electron shell by the magnetic moments of manganese neighbors, evidencing the presence of an uncompensated ferromagnetic moment within the manganese sublattice. The average magnetic moment of manganese was found to be around 2 & mu;B, strongly contrasting with the reported remnant magnetization of only 0.3 & mu;B. Moreover, the 55Mn NMR spectrum in-dicates the presence of magnetically non-equivalent manganese sites within this structure. The observed features of the 69,71Ga and 55Mn NMR spectra cannot be reconciled with any of the hitherto proposed collinear ar-rangements of manganese moments and suggest their non-collinear arrangement across a gallium layer. Nevertheless a more advanced study is required to elucidate the detailed nature of magnetic structure in this material.

Local magnetic properties of the ${\mathrm{Mn}}_{5}{\mathrm{Ge}}_{3}{\mathrm{C}}_{x}$(001) epitaxial films grown on Ge(111) with a nominal carbon concentration $0\ensuremath{\leqslant}x\ensuremath{\leqslant}0.85$ have been studied by means of $^{55}\mathrm{Mn}$ nuclear magnetic resonance (NMR). The NMR spectra were recorded from the demagnetized films and from the films fully magnetized along the $c$ direction as well as in the hexagonal $c$ plane. The data unambiguously show a synchronized carbon penetration of the crystal lattice ($D{8}_{8}$ structure, Nowotny phase, space group $P{6}_{3}/mcm$), occupying every second $2(b)$ void located within the chain of $\mathrm{Mn}[6(g)]$ octahedra and setting the limit for the carbon uptake into the ${\mathrm{Mn}}_{5}{\mathrm{Ge}}_{3}$ lattice at $x=0.5$. Moreover, the NMR data indicate that the chains of carbon-filled voids are correlated also in plane. Eventually, for the end concentration of $x=0.5$, a highly ordered superstructure is proposed, responsible for the observed two magnetically inequivalent positions within the $\mathrm{Mn}[4(d)]$ sublattice.

Local magnetic properties of the Mn5Ge3Cx (001) epitaxial films grown on Ge(111) with a nominal carbon concentration 0 <= x <= 0.85 have been studied by means of Mn-55 nuclear magnetic resonance (NMR). The NMR spectra were recorded from the demagnetized films and from the films fully magnetized along the c direction as well as in the hexagonal c plane. The data unambiguously show a synchronized carbon penetration of the crystal lattice (D8(8) structure, Nowotny phase, space group P6(3)/mcm), occupying every second 2(b) void located within the chain of Mn[6(g)] octahedra and setting the limit for the carbon uptake into the Mn5Ge3 lattice at x = 0.5. Moreover, the NMR data indicate that the chains of carbon-filled voids are correlated also in plane. Eventually, for the end concentration of x = 0.5, a highly ordered superstructure is proposed, responsible for the observed two magnetically inequivalent positions within the Mn[4(d)] sublattice.

Mn-55 NMR was used to investigate the effect of carbon doping on the local magnetic anisotropy in Mn5Ge3 epitaxial films (space-group P6(3)/mcm). It was found that carbon enters interstitially in the vicinity of the 6(g) crystallographic positions, occupying the 2(b) octahedral voids. The magnetic properties of the Mn atoms located in the corners of a host octahedron are strongly modified by the presence of carbon. Their magnetic moment is reduced by 0.7 mu(B) with respect to the pristine Mn5Ge3 film and the anisotropy of their orbital moment, measured as a difference between its value along the hexagonal c direction and on the c plane is reduced to 0.058 mu(B), whereas, in the pristine Mn5Ge3 films, it oscillated every 60 degrees between 0.151 mu(B) and 0. These changes are responsible for a significant decrease in magnetocrystalline anisotropy, which was reported to drop by an order of magnitude upon doping the Mn5Ge3 films with carbon.

Co-59 NMR (Nuclear Magnetic Resonance) has been used to investigate the distribution of Co-59 hyperfine fields in the Co1-xMox thin film alloys (0.01 < x < 0.1) co-deposited on V buffer. At x = 0 the films consisted of a mixture of fcc and hcp Co, and Mo was found to enter randomly the two Co fractions in the investigated concentration range. However, alloying with Mo was found to increase the amount of stacking faults, in agreement with the previously published results of theoretical calculations for binary alloys. A certain deviation from a random distribution of Mo, most probably due to the presence of magnetically induced miscibility gap for Co:Mo, has been identified for the alloys with Mo content larger than 1%. It was found that in the limit of a very small Mo concentration x approximate to 0, each Mo nearest neighbor lowers the Co-59 NMR resonance frequency by 43.8 MHz, i.e. the corresponding hyperfine field is reduced by 4.34 T, implying that Co atoms would become nonmagnetic when 5 Mo atoms enter as the nearest neighbors. However, the effect increases with concentration, due to the contribution from Mo in the more distant shells. The extrapolation to Mo concentration higher than the one used in the experiment predicts that Co becomes nonmagnetic when surrounded by 3 Mo nearest neighbors for the concentration as low as x = 0.2-0.25. (C) 2019 Elsevier B.V. All rights reserved.

Co-59 Nuclear Magnetic Resonance (NMR) and X-Ray Diffraction (XRD) has been used to investigate annealing effects on crystallographic structure and magnetic properties of ferromagnetic CoFeB layer in pseudo spin valves (P-SV): Ta/CoFeB/MgO/CoFeB and in an exchange bias spin valves (EB-SV): PtMn/CoFe/Ru/CoFeB/MgO/CoFeB magnetic tunnel junctions. It was found, that the as-deposited CoFeB layers in the P-SV and EB-SV are amorphous. The annealing treatment at 340 degrees C and 360 degrees C induces in all studied systems progressive phase segregation in CoFeB layer to areas of bcc CoFe regions displaying different degree of B2 order and to areas of an amorphous magnetic reminder with a higher B content. In the CoFeB layers grown on Ru (EB-SV) and Ta (P-SV) and covered by MgO in the upper interface, after annealing at 500 degrees C a state of substantially full phase segregation to B2 ordered bcc CoFe phase has been observed. The annealing at 500 degrees C of the CoFeB layers grown on MgO and covered by Ru in P-SV and EB-SV triggers extensive thermal diffusion and induces mixing at the CoFeB/Ru interface which transforms the CoFeB into a non-magnetic layer. Moreover, it has been found that CoFeB crystallizes better into the bcc CoFe (100) texture when deposited on Ta than on a Ru layer. XRD profiles show that while CoFeB layer is growing on Ru it crystallizes into bcc CoFe (110) oriented texture, and the one grown on Ta crystallizes into bcc CoFe (200) when annealed at 500 degrees C. Co-59 NMR restoring field analysis (H-rest-magnetic stiffness) showed that the insertion of the antiferromagnetic PtMn layer into the EB-SV system increases the magnetic hardness of the CoFeB layer by an order of the magnitude. However, adding CoFeB/MgO layers between PtMn/CoFe/Ru and CoFeB layers in the EB-SV decouples the CoFeB from the hard-magnetic system making it magnetically soft. (C) 2018 Elsevier B.V. All rights reserved.

Mn-55 NMR was used to perform the atomic-scale study of the anisotropic properties of Mn5Ge3/Ge(111) epitaxial films with thicknesses between 9 and 300 nm. The NMR spectra have been recorded as a function of strong external magnetic field applied in the film plane and perpendicular to it. Two Mn-55 NMR resonances have been observed, corresponding to the two manganese sites 4d and 6g, in the hexagonal D8(8) structure; in zero field their frequency is centered around 207.5 and 428 MHz, respectively. The anisotropy of 55Mn hyperfine fields between the hexagonal c direction and the c plane at both Mn sites was evidenced and attributed to the anisotropic term due to the unquenched Mn orbital momentum. The anisotropy of the orbital contribution to hyperfine fields was determined as 1.52 T in the 4d site and up to 2.77 T in the 6g site. The 4d site reveals a quadrupolar interaction due to the strong electric field gradient: V-zz = 5.3 x 10(19) V/m(2) in this site, which is shown to be oriented along the hexagonal c axis.

Magnetic properties of an ultrathin Co layer deposited on the Mo(1 1 0) or Au(1 1 1) buffers crucially depend on magnetic layer thickness and a cap layer type (Au or Mo, studied in this work). Depending on the sandwich configuration, magnetization is oriented in a perpendicular direction to the plane in the range of smaller Co layer thickness (below 2 nm) or in the sample plane for a thicker layer (3 nm). Moreover, a well-developed two-fold in-plane magnetic anisotropy occurs in the Co layer deposited on the Mo buffer. These features are correlated with crystalline structure studied with the use of numerous complementary methods: reflection high-energy electron diffraction, x-ray diffraction, x-ray reflectivity, nuclear magnetic resonance, and element-sensitive synchrotron techniques, i.e. x-ray linear dichroism and x-ray absorption near edge spectroscopy. Magnetic behaviour, exhibiting volume and surface contributions, is thoroughly discussed in terms of the buffer and cap layer type, thickness-dependent crystalline structure of the Co layer, and the interface quality.

Extensive X-band and Q-band FMR experiments have been performed in the Mn5Ge3 epitaxial films with thicknesses varying between 4.5 and 68 nm. FMR signals were recorded in the temperature range between 15 and 295 K, at different orientations of magnetic field with respect to the film plane. In addition to the acoustic FMR mode with well defined resonance field, originating from inside the magnetic domains, a broad absorption line has been observed at low fields and attributed to the unresolved spectrum of FMR modes having the origin in flux closure caps. The FMR results have been discussed in the context of the domain structure computed with the use of OOMMF micromagnetic calculations and giving good agreement with the experimental hysteresis curves. From the Q-band experiments, where the FMR signal is observed in the magnetically saturated sample, the uniaxial anisotropy constant in films with different thicknesses has been determined as a function of temperature. This FMR study provides the evidence that the strong uniaxial anisotropy observed in epitaxial thin films of Mn5Ge3 leads to the formation of a stripe domain structure above 25 nm, in agreement with the published reports on magnetization studies in these films. It also eliminates a possible confusion that may arise from previously published FMR studies on films grown with the same method, which led their authors to conclude that the shape anisotropy can force the magnetization to the in-plane orientation in this thickness range and even above it.

Heusler compounds exhibit different electronic ground states and functionalities, making them attractive for studies of their fundamental properties and for their technological exploitation. A key tool in the rational design of this class of materials is the precise control of the relationships between structure and physical properties since Heusler compounds are known to order in various structure types. This review describes the different types of order in Heusler compounds, identifies methods to analyze the local crystallographic and magnetic order as well as illustrates the effect of order on the properties of Heusler compounds by discussing recent examples of studies addressing order in Heusler compounds.

Mixed-valence manganites La(1-x)A(x)MnO(3) (A = Sr, Ca) with x approximate to 0.5 can be driven from a ferromagnetic-metallic to an antiferromagnetic-insulating state by a small modification (Delta x) of the carrier density (Delta x/x < 1). For this reason, these oxides have received renewed attention due to their potentially advantageous integration in ferroelectric tunnel junctions of adjustable tunnel barrier width. Interestingly, in thin films, epitaxial strain can modify the electronic and magnetic ground state strongly affecting their magnetotransport properties. Here we exploit the extreme sensitivity of linearly and circularly polarized x-ray absorption to orbital anisotropy and magnetic ordering to explore the role of structural distortions and electronic bandwidth on the orbital occupancy and spin ordering of Mn 3d states in La(0.5)A(0.5)MnO(3) films under various strain states. Mn-55 NMR experiments are used to get information about the electronic and magnetic phase separation and orbital ordering occurring in these films. These results combined with the corresponding structural, magnetic, and electrical characterization allow us to map the strain-dependent orbital and magnetic phase diagrams of half-doped manganites and its dependence on the electronic bandwidth.

Biotransformation processes accompanied by whole yeast cells as biocatalyst are a promising area of food industry. Among the chemical sanitizers currently used in food technology, hydrogen peroxide is a very effective microbicidal and bleaching agent. In this paper, permeabilization has been applied to Saccharomyces cerevisiae yeast cells aiming at increased intracellular catalase activity for decomposed H2O2. Ethanol, which is non-toxic, biodegradable and easily available, has been used as permeabilization factor. Response surface methodology (RSM) has been applied in determining the influence of different parameters on permeabilization process. The aim of the study was to find such values of the process parameters that would yield maximum activity of catalase during decomposition of hydrogen peroxide. The optimum operating conditions for permeabilization process obtained by RSM were as follows: 53% (v/v) of ethanol concentration, temperature of 14.8 °C and treatment time of 40 min. After permeabilization, the activity of catalase increased ca. 40 times and its maximum value equalled to 4711 U/g.