WorldCat Identities

Petruhins, Andrejs

Overview
Works: 19 works in 22 publications in 2 languages and 24 library holdings
Roles: Author, Other
Publication Timeline
.
Most widely held works by Andrejs Petruhins
Synthesis and characterization of Ga-containing MAX phase thin films by Andrejs Petruhins( )

3 editions published in 2014 in English and held by 3 WorldCat member libraries worldwide

Synthesis and characterization of magnetic nanolaminated carbides by Andrejs Petruhins( Book )

2 editions published in 2018 in Swedish and English and held by 2 WorldCat member libraries worldwide

Synthesis and characterization of magnetic (Cr0.5Mn0.5)2GaC thin films by Andrejs Petruhins( )

1 edition published in 2015 in English and held by 2 WorldCat member libraries worldwide

Large uniaxial magnetostriction with sign inversion at the first order phase transition in the nanolaminated Mn2GaC MAX phase by Iuliia P Novoselova( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

Effect of Ti-Al cathode composition on plasma generation and plasma transport in direct current vacuum arc by Igor Zhirkov( )

1 edition published in 2014 in English and held by 1 WorldCat member library worldwide

DC arc plasma from Ti, Al, and Ti1-xAlx (x = 0.16, 0.25, 0.50, and 0.70) compound cathodes was characterized with respect to plasma chemistry and charge-state-resolved ion energy. Scanning electron microscopy, X-ray diffraction, and Energy-dispersive X-ray spectroscopy of the deposited films and the cathode surfaces were used for exploring the correlation between cathode-, plasma-, and film composition. Experimental work was performed at a base pressure of 10( -6) Torr, to exclude plasma-gas interaction. The plasma ion composition showed a reduction of Al of approximately 5 at. % compared to the cathode composition, while deposited films were in accordance with the cathode stoichiometry. This may be explained by presence of neutrals in the plasma/vapour phase. The average ion charge states (Ti = 2.2, Al = 1.65) were consistent with reference data for elemental cathodes, and approximately independent on the cathode composition. On the contrary, the width of the ion energy distributions (IEDs) were drastically reduced when comparing the elemental Ti and Al cathodes with Ti0.5Al0.5, going from similar to 150 and similar to 175 eV to similar to 100 and similar to 75 eV for Ti and Al ions, respectively. This may be explained by a reduction in electron temperature, commonly associated with the high energy tail of the IED. The average Ti and Al ion energies ranged between similar to 50 and similar to 61 eV, and similar to 30 and similar to 50 eV, respectively, for different cathode compositions. The attained energy trends were explained by the velocity rule for compound cathodes, which states that the most likely velocities of ions of different mass are equal. Hence, compared to elemental cathodes, the faster Al ions will be decelerated, and the slower Ti ions will be accelerated when originating from compound cathodes. The intensity of the macroparticle generation and thickness of the deposited films were also found to be dependent on the cathode composition. The presented results may be of importance for choice of cathodes for thin film depositions involving compound cathodes
Deposition of MAX phase-containing thin films from a (Ti,Zr)(2)AlC compound target by Clio Azina( )

1 edition published in 2021 in English and held by 1 WorldCat member library worldwide

This work reports on sputter depositions carried out from a compound (Ti,Zr)(2)AlC target on Al2O3(0 0 0 1) substrates at temperatures ranging between 500 and 900 degrees C. Short deposition times yielded 30-40 nm-thick Al-containing (Ti,Zr)C films, whereas longer depositions yielded thicker films up to 90 nm which contained (Ti,Zr)C and intermetallics. At 900 degrees C, the longer depositions led to films that also consisted of solid solution MAX phases. Detailed transmission electron microscopy showed that both (Ti,Zr)(2)AlC and (Ti,Zr)(3)AlC2 solid solution MAX phases were formed. Moreover, this work discusses the growth mechanism of the thicker films, which started with the formation of the mixed (Ti,Zr)C carbide, followed by the nucleation and growth of aluminides, eventually leading to solid state diffusion of Al within the carbide, at the highest temperature (900 degrees C) to form the MAX phases
Atomically Layered and Ordered Rare-Earth i-MAX Phases: A New Class of Magnetic Quaternary Compounds by Quanzheng Tao( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

In 2017, we discovered quaternary i-MAX phases atomically layered solids, where M is an early transition metal, A is an A group element, and X is C-with a ((M2/3M1/32)-M-1)(2)AC chemistry, where the M-1 and M-2 atoms are in-plane ordered. Herein, we report the discovery of a class of magnetic i-MAX phases in which bilayers of a quasi-2D magnetic frustrated triangular lattice overlay a Mo honeycomb arrangement and an Al Kagome lattice. The chemistry of this family is (Mo2/3RE1/3)(2)AlC, and the rare-earth, RE, elements are Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu. The magnetic properties were characterized and found to display a plethora of ground states, resulting from an interplay of competing magnetic interactions in the presence of magnetocrystalline anisotropy
Phase stability of Crn+1GaCn MAX phases from first principles and Cr2GaC thin-film synthesis using magnetron sputtering from elemental targets by Andrejs Petruhins( )

1 edition published in 2013 in English and held by 1 WorldCat member library worldwide

Ab-initio calculations have been used to investigate the phase stability and magnetic state of Crn+ 1GaCn MAX phase. Cr2GaC (n = 1) was predicted to be stable, with a ground state corresponding to an antiferromagnetic spin configuration. Thin-film synthesis by magnetron sputtering from elemental targets, including liquid Ga, shows the formation of Cr2GaC, previously only attained from bulk synthesis methods. The films were deposited at 650 degrees C on MgO(111) substrates. X-ray diffraction and high-resolution transmission electron microscopy show epitaxial growth of (000) MAX phase
Synthesis of atomically layered and chemically ordered rare-earth (RE) i -MAX phases; (Mo 2/3 RE 1/3) 2 GaC with RE = Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu by Andrejs Petruhins( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

We report the synthesis of eight new members of the i -MAX family, of the formula (Mo 2/3 RE 1/3) 2 GaC, where RE = Gd, Tb, Dy, Ho, Er, Tm, Lu, and Yb, the latter not previously incorporated in a MAX phase. The structure and composition of powder samples were investigated by X-ray diffraction, scanning transmission electron microscopy, and energy dispersive X-ray analysis combined with scanning electron microscopy. All phases showed evidence of an orthorhombic (Cmcm) structure, and the phases based on Er and Yb also crystallized in a monoclinic (C 2/ c) arrangement. The chemical order of the magnetic elements suggests interesting magnetic characteristics, with a high tuning potential through the range of attainable lanthanide elements
Theoretical Prediction and Experimental Verification of the Chemically Ordered Atomic-Laminate i-MAX Phases (Cr2/3Sc1/3)(2)GaC and (Mn2/3Sc1/3)(2)GaC by Andrejs Petruhins( )

1 edition published in 2020 in English and held by 1 WorldCat member library worldwide

We combine predictive ab initio calculations with experimental verification of bulk materials synthesis for exploration of new and potentially magnetic atomically laminated i-MAX phases. Two such phases are discovered: (Cr2/3Sc1/3)(2)GaC and (Mn2/3Sc1/3)(2)GaC synthesized by the solid state reaction from elemental constituents. The latter compound displays a 2-fold increase in Mn content compared to previously reported bulk MAX phases. Both new compounds exhibit the characteristic in-plane chemical order of Cr(Mn) and Sc, and crystallize in an orthorhombic structure, space group Cmcm, as confirmed by scanning transmission electron microscopy. From density functional theory calculations of the magnetic ground state, including the electron-interaction parameter U, we suggest an antiferromagnetic ground state, close to degenerate with the ferromagnetic state
Mn3GaC inverse perovskite thin films by magnetron sputtering from elemental targets by Andrejs Petruhins( )

1 edition published in 2020 in English and held by 1 WorldCat member library worldwide

We have deposited epitaxial thin films of the inverse perovskite Mn3GaC using magnetron sputtering from elemental targets. Two substrates were used, MgO (111) and (100), resulting in corresponding orientation of the Mn3GaC thin films. Both samples displayed magnetic properties consistent with an AFM to FM transition at similar to 170 K and a Curie temperature around 265 K, evaluated with vibrating sample magnetometry (in-plane measurements). These two ground states are further supported by first principles calculations. Based on that the two orientations of Mn3GaC display very similar magnetic properties, it can be concluded that shape anisotropy dominates over the materials easy axis
Long-term stability and thickness dependence of magnetism in thin (Cr0.5Mn0.5)(2)GaC MAX phase films by Iuliia P Novoselova( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

The thickness dependence and long-term stability of the magnetic properties of epitaxial (Cr0.5Mn0.5)(2)GaC MAX phase films on MgO (111) were investigated. For 12.5- to 156-nm-thick films, which corresponds to 10-125 c-axis unit cells, samples were found to be phase pure with negligible c-axis lattice strain of less than 10( -4) nm even for the thinnest films. No influence of the interface layers on the magnetic anisotropy, the magnetization or the para- to ferromagnetic phase transition was observed. All samples remained stable for more than one year in ambient conditions. [GRAPHICS] IMPACT STATEMENT The complex temperature- and magnetic field-dependent magnetism of electrically conducting (Cr0.5Mn0.5)(2)GaC MAX phase films is environmentally robust over one year and independent on interface effects
Effect of Mo-Cu cathode composition on process stability, macroparticle formation, plasma generation, and thin-film deposition in DC arc synthesis by Igor Zhirkov( )

1 edition published in 2020 in English and held by 1 WorldCat member library worldwide

In this work, we present the correlation between cathode composition and features of the arcing process for Mo1-xCux [x = 0.0, 0.07 (0.05), 0.14 (0.10), 0.21 (0.15), 0.40 (0.3), 0.73 (0.63), 0.97 (0.95), and 1.00, atomic fraction (weight fraction)] cathodes used in a DC vacuum-arc deposition system. It is found that the stability of the arcing process crucially depends on the cathode composition. The most stable arc spot and the lowest cathode potential (similar to 19 V) are detected for the Mo0.27Cu0.73 cathode, while the Mo0.93Cu0.07 cathode shows the most unstable arcing process with the highest cathode potential (similar to 28 V). The properties of the generated plasma are also strongly dependent on the relative ratio of the cathode elements. The metal ions from the Mo and Cu cathodes have peak kinetic energies around 136 and 62 eV, respectively, while for a Mo0.79Cu0.21 cathode, the corresponding energies are only 45 and 28 eV. The average charge states decreased from 2.1 to 1.6 for Mo ions and from 2 to 1.2 for Cu ions. The intensity of macroparticle generation and the size of the droplets correlate with the relative fraction of Cu. However, it is shown that, typically for the cathodes with a low amount of Cu, an increased abundance of visually observed macroparticles leads to droplet-free films. The film thicknesses and their compositions also demonstrate dependencies on the elemental composition of the cathode. These results are discussed in the light of no solubility between Mo and Cu and the high temperature of the cathode surface during the arcing process. Published under license by AIP Publishing
Formation of Ti2AuN from Au-Covered Ti2AlN Thin Films: A General Strategy to Thermally Induce Intercalation of Noble Metals into MAX Phases by Shun Kashiwaya( )

1 edition published in 2020 in English and held by 1 WorldCat member library worldwide

Thermally induced intercalation of noble metals into non-van der Waals ceramic compounds presents a method to produce a new class of layered materials. We recently demonstrated an exchange reaction of Au with A layers of MAX phase carbides with plentiful combinations of A and M elements. Here, we report the first substitution of Al with Au in a Ti2AlN MAX phase nitride at an elevated temperature without destroying the original layered structure. These results bolster the generalization of the Au intercalation for the A elements in MAX phases with diverse combinations of M, A, and X elements. Furthermore, we propose crucial factors to achieve the exchange reaction: there should be a chemical potential for the A element to dissolve in or react with noble metals to intercalate; the noble metals should be inert to the initial metal carbides/nitrides; and it is necessary to choose the reaction temperature that allows balanced interdiffusion of the noble metals and A elements
Effect of Ti-Al cathode grain size on plasma generation and thin film synthesis from a direct current vacuum arc plasma source by Igor Zhirkov( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

Herein, we investigate the influence of powder metallurgical manufactured Ti0.5Al0.5 cathode grain size (45-150 mu m) on the properties of a DC arc discharge, for N-2 pressures in the range 10( -5) Torr (base pressure) up to 3x10( -2) Torr. Intermetallic TiAl cathodes are also studied. The arc plasma is characterized with respect to ion composition, ion charge state, and ion energy, and is found to change with pressure, independent on choice of cathode. Scanning electron microscopy, X-ray diffraction, and Energy-dispersive X-ray spectroscopy of the cathode surfaces and the concurrently deposited films are used for exploring the correlation between cathode-, plasma-, and film composition. The plasma has a dominating Al ion content at elevated pressures, while the film composition is consistent with the cathode composition, independent on cathode grain size. Cross-sections of the used cathodes are studied, and presence of a converted layer, up to 10 mu m, is shown, with an improved intermixing of the elements on the cathode surface. This layer is primarily explained by condensation of cathode material from the melting and splashes accompanying the arc spot movement, as well as generated plasma ions being redeposited upon returning to the cathode. The overall lack of dependence on grain size is likely due to similar physical properties of Ti, Al and TiAl grains, as well as the formation of a converted layer. The presented findings are of importance for large scale manufacturing and usage of Ti-Al cathodes in industrial processes. (C) 2019 Author(s)
Synthesis and characterization of CrB 2 thin films grown by DC magnetron sputtering by Megan Dorri( )

1 edition published in 2021 in English and held by 1 WorldCat member library worldwide

CrB x thin films with 1.90 < x < 2.08 have been deposited by direct-current magnetron sputtering (DCMS) from a stoichiometric CrB 2 target at 5 and 20 mTorr (0.67 and 2.67 Pa) Ar pressure onto sapphire (0 0 01) substrates. All films, irrespective of deposition conditions, exhibit a (0 0 01) texture. Attesting to the achievement of close-to-stoichiometric composition, epitaxial film growth is observed at 900 ?C, while film growth at 500 ?C yields (0001) fiber texture. Film composition does not depend on substrate temperature but exhibits slightly reduced B content with increasing pressure for samples deposited at 900 ?C. Excess B in the overstoichiometric epitaxial CrB 2.08 films segregates to form B-rich inclusions. Understoichiometry in CrB 1.90 films is accommodated by Cr-rich stacking faults on { 1 1? 00 } prismatic planes. ? 2021 The Author(s). Published by Elsevier Ltd on behalf of Acta Materialia Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )
Magnetic properties and structural characterization of layered (Cr0.5Mn0.5)(2)AuC synthesized by thermally induced substitutional reaction in (Cr0.5Mn0.5)(2)GaC by Chung-Chuan Lai( )

1 edition published in 2018 in English and held by 1 WorldCat member library worldwide

The magnetic properties of the new phase (Cr0.5Mn0.5)(2)AuC are compared to the known MAX-phase (Cr0.5Mn0.5)(2)GaC, where the former was synthesized by thermally induced substitution reaction of Au for Ga in (Cr0.5Mn0.5)(2)GaC. The reaction introduced a lattice expansion of similar to 3% along the c-axis, an enhancement of the coercive field from 30 mT to 140 mT, and a reduction of the Curie temperature and the saturation magnetization. Still, (Cr0.5Mn0.5)(2)AuC displays similar features in the magnetic field-and temperature-dependent magnetization curves as previously reported magnetic MAX phases, e.g., (Cr0.5Mn0.5)(2)GaC and (Mo0.5Mn0.5)(2)GaC. Thework suggests a pathway for tuning the magnetic properties of MAX phases. (c) 2018 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license
Structural and mechanical properties of amorphous AlMgB14 thin films deposited by DC magnetron sputtering on Si, Al2O3 and MgO substrates by Mohammad Noroozi( )

1 edition published in 2020 in English and held by 1 WorldCat member library worldwide

AlMgB14 coatings have been deposited by DC magnetron sputtering from elemental targets on Si (001), Al2O3 (0001) and MgO (001) substrates at temperatures in the range of 25-350 degrees C. The structural and mechanical properties of AlMgB14 films were characterized by X-ray diffraction, scanning electron microscopy, nanoindentation, and analyzed as a function of deposition conditions and substrate materials. The results show that all films are X-ray amorphous, and the mechanical properties of the deposited films depend on the substrate and growth temperature. AlMgB14 thin films deposited at 350 degrees C are found to have smoother surfaces and containing more well-formed B-12 icosahedra than the films deposited at lower temperature, which consequently increase the hardness of the deposited films. The maximum hardness and Youngs modulus of the as-deposited films are about 32.3 GPa and 310 GPa, respectively, for films deposited on Al2O3 substrate at 350 degrees C
Direct measurement of anisotropic conductivity in a nanolaminated (Mn0.5Cr0.5)(2)GaC thin film by Tim Flatten( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

The direct and parameter-free measurement of anisotropic electrical resistivity of a magnetic M(n+1)AX(n) (MAX) phase film is presented. A multitip scanning tunneling microscope is used to carry out 4-probe transport measurements with variable probe spacing s. The observation of the crossover from the 3D regime for small s to the 2D regime for large s enables the determination of both in-plane and perpendicular-to-plane resistivities rho(ab) and rho(c). A (Cr0.5Mn0.5)(2)GaC MAX phase film shows a large anisotropy ratio rho(c)/rho(ab) = 525 +/- 49. This is a consequence of the complex bonding scheme of MAX phases with covalent M-X and metallic M-M bonds in the MX planes and predominately covalent, but weaker bonds between the MX and A planes. Published under license by AIP Publishing
 
moreShow More Titles
fewerShow Fewer Titles
Audience Level
0
Audience Level
1
  General Special  
Audience level: 0.95 (from 0.85 for Synthesis ... to 0.97 for Large unia ...)

Languages