bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetization studies of HoCo0.51Mn0.49O3 single crystals
Authors: Aleshkevych P. , Baran M. , Barilo S. N. , Gatalskaya V. I. , Shiryaev S. V. , Szymczak R. , Szymczak H. 
Published: January 2006

AbstractThe low‐temperature magnetic properties of the orthorhombic HoMn0.49Co0.51O3 single crystals grown by the electrodeposition method have been investigated. From an analysis of magnetization results two types of phase transitions were found. The first‐order transition is connected with ferromagnetic ordering (the Curie temperature T C = 83 K). The second‐order transition accompanied by spontaneous spin reorientation was found within the 20–30 K range of temperature. The spin reorientation was explained in the framework of the phenomenological molecular field model. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The origin of low‐dimensional magnetism in Cu(en )2Pt(CN)4
Authors: Tibenská K. , Orendáčová A. , Čižmár E. , Park J.‐H. , Lančarič Š. , Orendáč M. , Anders A. G. , Vavra M. , Potočňák I. , Feher A. , Meisel M. W. 
Published: January 2006

AbstractMagneto‐structural correlations in Cu(en )2Pt(CN)4 (en = C2H8N2) have been investigated by experimental studies of the magnetic properties and hydrogen bond geometry. The analysis of electron paramagnetic resonance spectra confirmed the d z2 electronic ground state of Cu(II) ion expected from room temperature X‐ray measurements. Magnetization and susceptibility data indicate the presence of weak exchange coupling J /k B = –0.4 K. Consequently, a spin diffusive regime in the spin relaxation can be expected at 4 K, and the angular dependence of the linewidth can be qualitatively explained by considering two‐dimensional magnetic behaviour. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phase diagram of hard‐core bosons with both diagonal and Mattis‐type off‐diagonal disorder
Authors: Grzybowski P. , Chhajlany R. W. 
Published: January 2006

AbstractWe reanalyze the phase diagram of a hard‐core boson system with diagonal and Mattis‐type off‐diagonal disorder in a general setting. We report differences with respect to previously presented results. In an extended model, we have found an additional continuous transition not present in the previously studied case. We also comment on the influence of the interplay between the diagonal and off‐diagonal disorder on the existence of the localization transition. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the BCS‐to‐Bose crossover in 2D anisotropic superconductors
Authors: Tobijaszewska B. , Micnas R. 
Published: January 2006

AbstractWe analyze the competing pairings and crossover from BCS to local pair (LP) superconductivity for the d‐wave pairing symmetry in the ground state. The phase diagrams for the extended Hubbard model with intersite electron pairing and hard‐core repulsion (U = ∞) are obtained for the 2D square lattice. The influence of the nnn hopping (t 2) on the crossover is discussed. For appropriate values of the parameters (nnn repulsion) and |t 2/t | < 0.5 the crossover is simultaneous with the vanishing of nodal points in the quasiparticle energy. The vanishing of nodal points is clearly reflected in the evolution of the presented superconducting characteristics. Results for d pairing are compared with those for the crossover in the s*‐wave channel and the role of chiral px + i py states is also discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Monte‐Carlo simulation of solid state and melting of 2D confined magnetic particles under perpendicular field
Authors: Levy Jean‐Claude S. , Ghazali Abdelwahab 
Published: January 2006

AbstractNumerous systems correspond to confined magnetic particles interacting through dipolar interactions: magnetic particles, flux lines in superconductors, charged colloids. From careful extended Monte‐Carlo simulations the ground state is obtained and shown to be derived from a triangular lattice with a few layers stuck to the confinement boundary. The most common solid state obtained by relaxation from a random configuration is found to be an excited state composed of many triangular crystallites separated by lines of alternate topological defects with five and seven nearest neighbours. The melting of these two solid phases gives a common liquid phase. But the melting of the ground state is a sharp first order transition while the melting of the excited state is a continuous vitreous transition which starts at low temperature with the motion of topological defects on their defect lines, while the rest of the sample remains solid, as a two component medium. The elastic properties of these solid states under shear are also considered. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Current‐induced spin dynamics in spin‐valve structures
Authors: Gmitra M. , Horváth D. , Wawrzyniak M. , Barnaś J. 
Published: January 2006

AbstractThe Landau–Lifshitz–Gilbert equation for the magnetization dynamics, extended by including the torque due to spin‐transfer from conduction electrons, is used to study current‐induced magnetic switching and stationary precessional modes. The spin torque is described in terms of a macroscopic model based on the classical spin diffusion equations and relevant boundary conditions. The approach allows to investigate current‐driven switching, in particular the switching time and the frequency of the associated magnetoresistance signal in the precessional regime. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of hydrogen bonds on magnetic properties of Cu(dmen )2M(CN)4 (M = Ni, Pt) S = 1/2 low‐dimensional Heisenberg antiferromagnets
Authors: Čižmár E. , Orendáčová A. , Orendáč M. , Kuchár J. , Vavra M. , Potočňák I. , Černák J. , Casini E. , Feher A. 
Published: January 2006

AbstractThe magneto‐structural correlations in materials Cu(dmen )2M(CN)4, where M = Ni or Pt, and dmen is N,N‐dimethylethylenediamine, have been investigated. Specific heat, susceptibility, magnetization and ESR studies of both materials suggest the presence of a weak antiferromagnetic (AFM) exchange interaction. Observed l ‐like anomaly at T max = 0.2 K in the temperature dependence of the specific heat of studied materials might be attributed to the formation of long‐range order due to the presence of exchange coupling between the planes. The entropy removed above the transition temperature represents 50% of the total magnetic entropy suggesting low‐dimensional character of the system. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermal stability of amorphous structure and magnetic properties Fe80–xCoxP14B6 (x = 20–40) ribbons
Authors: Kostyrya S. A. , Idzikowski B. , Tkatch V. I. , Popov V. V. , Rassolov S. G. 
Published: January 2006

AbstractAmorphous structure and its thermal stability as well as magnetic properties of Fe80–x Cox P14B6 (20 ≤ x ≤ 40) glasses have been studied by X‐ray diffraction, non‐isothermal differential scanning calorimetry (DSC) and thermomagnetic (TMG) measurements. The Curie temperature increases with Co content, while the glass transition and crystallization onset temperatures decrease. As a result, for alloys x = 30, 32 and 35 at%, the transition into paramagnetic state take place close to glass transition temperature. However, for x = 40 at% the TMG curve, in the vicinity of magnetic transition temperature, is overlapped by ferromagnetic crystallization products. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural, magnetic and hyperfine parameters of B2‐type FeAl compounds doped with transition metal additions
Authors: Michalecki T. , Deniszczyk J. , Frackowiak J. E. 
Published: January 2006

AbstractThe structural, electronic and magnetic properties of the transition metal (TM = Ti, V, Cr, Mn, Co, Ni, Cu, Zn) alloying additions in FeAl compound with B2 structure have been investigated with tight‐binding linear muffin‐tin orbital (TB‐LMTO) method. The site preference of the TM additions was investigated for (Fe0.44TM0.06)Al0.50 and Fe0.50(Al0.44 TM0.06) compositions. Both magnetically ordered and non magnetic solutions were analysed. The analysis has shown that the elements (Ti, V, Cr, Mn) slightly more prefer the Al sublattice, whereas the (Co, Ni, Cu, Zn) atoms have a distinct preference for the Fe sublattice. The local magnetic moment of the additions located at the Al sites shows an antiferromagnetic alignment with respect to the bulk magnetization. The dependence of the isomer shift and hyperfine magnetic field for 57Fe nucleus on the TM valence is analysed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic properties of substituted SrRuO3
Authors: Dabrowski B. , Kolesnik S. , Chmaissem O. , Maxwell T. , Mais J. , Jorgensen J. D. 
Published: January 2006

AbstractWe have investigated structural and magnetic properties of the SrRu1–v O3 and SrRu1–x Crx O3 perovskites with uniquely suppressed and increased ferromagnetic transition temperatures, respectively. Polycrystalline samples synthesized in 600 atm. O2 at 1100 °C and in air at 1340 °C reach the v and Cr solubility limits at v ∼ 0.10 and x = 0.15, respectively. The ordered moment is dramatically suppressed by the creation of Ru vacancies. The linear decrease of the lattice parameters and bond lengths, and an increase of the bond angles with increasing x are due to substitution of the smaller Cr4+/3+ ion for Ru4+/5+. Similar decreases of the molar susceptibility, χ m, in the paramagnetic region above T C and the high‐field magnetization at 5 K with x also indicate the presence of the Cr4+/3+ and Ru4+/5+ ions. These results confirm that the Ru4+/5+(d4/3)–O2––Cr4+/3+(d2/3) minority band double‐exchange interaction that involves the Cr3+ and Cr4+ in the magnetic ordering is responsible for the enhanced ordering temperature. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic properties of almost localized fermions revisited: spin dependent masses and quantum critical behavior
Authors: Spałek Jozef 
Published: January 2006

AbstractThe magnetic properties of almost localized (heavy) quasiparticles have been a subject of renewed interest in recent years. This is caused by the discovery of spin dependent masses predicted by us some time ago, as well as quantum critical behavior at the metal–insulator boundary. We discuss those phenomena, as well as metamagnetic behavior. These phenomena are discussed by regarding Gutzwiller approach (in the slave‐boson version) as the mean‐field approach to the correlated electron systems. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic properties of almost localized fermions revisited: spin dependent masses and quantum critical behavior
Authors: Spałek Jozef 
Published: January 2006

AbstractThe Editor's Choice [1] of this issue of physica status solidi (b) discusses spectacular phenomena in correlated electron systems viewed as quantum materials. The cover figure is a schematic representation of the transformation from the Kondo insulator (KI) state to the non‐Fermi liquid (NFL) state with short‐range antiferromagnetic correlations at the critical concentration, when the Kondo singlet state is destroyed. AFI denotes the antiferromagnetic insulating state.The author Jozef Spałek heads the Condensed Matter Theory Division in the Institute of Physics of the Jagiellonian University Kraków. His scientific interests include the theory of Mott–Hubbard and heavy‐fermion systems, with a particular emphasis on quantum critical behavior close to the electron localization.This issue contains presentations from The European Conference Physics of Magnetism (PM'05) held in Poznań, Poland, 24–27 June 2005. Further articles from PM'05 can be found in phys. stat. sol. (c) 3, No. 1 (2006).
Bond‐ordered, bond‐centered stripes in cuprates
Authors: Maciąg A. , Wróbel P. , Eder R. 
Published: January 2006

AbstractUsing a combination of the bond formalism and the string picture we analyze the stability of bond‐ordered, bond‐centered stripe system formed in the doped two dimensional (2D) antiferromagnet (AF). Our interest in such structures is motivated by results of recent neutron scattering experiments. We concentrate especially on a stripe, in which bond order takes the shape of a two‐layer brick wall, forming a domain wall (DW) between AF domains with the changing by π across each DW direction of the sublattice magnetization. By analyzing the energy of such a structure and comparing with energies of stripes with other patterns of the underlying magnetic background we draw the conclusion that at the doping level 1/8 the most stable is the system of DWs which takes the form of two‐leg ladders with bond‐ordered nearest parallel legs. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two‐band ferromagnetic Kondo lattice model on a ladder with quantum S = 3/2 core spins
Authors: Neuber D. R. , Daghofer M. , Olés Andrzej M. , von der Linden Wolfgang 
Published: January 2006

AbstractThe interplay of spin and orbital correlations in doped manganites is investigated on a ladder described by the ferromagnetic (FM) Kondo model. Upon doping, the one‐band model exhibits phase separation into an antiferromagnetic (AF) background due to t 2g superexchange J ′ and either a hole‐rich FM phase or islandlike region of antiferromagnetically stacked polarons. In contrast, separated polarons are favored by the two‐band model at low doping. For suitable parameters, both the one‐orbital and two‐orbital model yield FM chains with AF coupling between them, reminiscent of the C ‐AF phase observed in manganites. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Intrinsic mechanism of anomalous Hall effect in a twodimensional magnetic system with impurities
Authors: Dugaev V. K. , Bruno P. , Taillefumier M. , Canals B. , Lacroix C. 
Published: January 2006

AbstractWe report some new results on the Anomalous Hall effect induced by the Berry phase in momentum space. Our main calculations are performed within the model of a two‐dimensional electron gas with the spin‐orbit interaction of Rashba type, taking into account the scattering from impurities. We demonstrate that such an “intrinsic” mechanism can really dominate but there is a competition between the geometric Berry‐phaseinduced term σ II xy in the Hall conductivity and the impurity‐induced term σ I xy , related to the contribution of the states in the vicinity of the Fermi surface. We also show that the contribution to the Hall conductivity from the electron states close to the Fermi surface has the intrinsic property as well, and it does not vanish in the clean limit. The main effect of the impurity‐related contribution is a possible change of sign of the off‐diagonal conductivity. The resulting magnitude and sign of the Hall conductivity strongly depend on the electron density in the system. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Domain structure and magnetoresistance of NiFe/Au/Co/Au multilayers with perpendicular anisotropy
Authors: Urbaniak Maciej , Stobiecki Feliks , Engel Dieter , Szymański Bogdan , Ehresmann Arno , Kim JinBae 
Published: January 2006

AbstractThe magnetic properties of sputtered [Ni80Fe20(2 nm)/Au(t Au)/Co(t Co)/Au(t Au)]15 multilayers with t Au = 1.5‐3 nm and t Co =0.6‐1.5 nm were investigated with magnetic force microscope. The Ni80Fe20 layers possessed in‐plane magnetic anisotropy while the sandwiching of Co layers between Au layers ensured their perpendicular anisotropy through the influence of surface anisotropy. It led to the formation of a maze configuration of stripe domains. The stripe domains period λ strongly depends on t Co changing from 0.9 to 0.3 µm when t Co changes from 0.6 to 0.8 nm. Period λ increases with Au layers thickness, too. The values of stray fields originating from Co layers which act on Ni80Fe20 layers, in the range of 100 kA/m, estimated from magnetoresistive dependencies are in qualitative agreement with those evaluated from the model of infinitely long stripe domains with domain widths taken from MFM measurements. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical transport in strained La0.7Ca0.3MnO3 films
Authors: Markovich V. , Vlakhov E. S. , Yuzhelevskii Y. , Blagoev L. B. , Nenkov K. A. , Gorodetsky G. 
Published: January 2006

AbstractMagnetotransport properties of La0.7Ca0.3MnO3 thin films deposited on (100) LaAlO3 substrate were investigated. Fine balance between the charge ordered insulating phase and ferromagnetic metallic phase results in a number of glassy features such as: significant hysteresis, memory effects and long‐time resistivity relaxation at turning on and off of magnetic field. It was found that in the temperature range 10–220 K the resistance of thin film decreases significantly upon applying electric current and this effect cannot be explained by homogeneous Joule heating. The magnetotransport properties of the thin films are discussed in the frame of cross‐coupling of charge, spin and strain. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin wave parameter in the system of non‐equivalent exchange coupled layers
Authors: Urbaniak‐Kucharczyk A. , Castillo Alvarado F. L. 
Published: January 2006

AbstractThe system of two ferromagnetic layers characterized by different exchange parameters and indirectly coupled by nonmagnetic spacer has been considered in low temperature region. The spin wave parameter B describing the Bloch's T 3/2 law has been calculated as a function of thickness and exchange parameters of constituent layers employing the Green fuction method. It has been shown that anisotropy in the interface region influences the dependence of B on the inverse thickness of the system. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transport and magnetic characterization of La0.885Sr0.115MnO3/YBa2Cu3O7 superlattices
Authors: Tsarou A. , Komissarov I. , Dluzewski P. , Paszkowicz W. , Minikayev R. , Sawicki M. , Dabrowski B. , Kimaball C. , Przyslupski P. 
Published: January 2006

AbstractWe report on depression of superconducting transition temperature of YBa2Cu3O7 (YBCO) layers, when their thickness is reduced in proximity to ferromagnetic insulating La0.885Sr0.115MnO3 (FI‐LSMO) layers in [FI‐LSMO*8 u.c./YBCO*n u.c.]16 superlattices, where n = 1, 2, 4 and 6 unit cells (u.c.). The thickness of manganite FI‐LSMO layers is kept at 8 unit cells. Signature of antiparallel alignment between FI‐LSMO layers across YBCO spacer layers was observed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin‐polarized surface states in semiconductor superlattices
Authors: Kłos Jarosław 
Published: January 2006

AbstractElectronic surface states in Al0.1Ga0.9As|GaAs superlattice are calculated for a system with a ZnMnSe barrier in a surface cell. In the absence of applied magnetic field the ZnMnSe barrier has the same height as the Al0.1Ga0.9As barriers in the bulk cells. When a magnetic field is applied perpendicularly to the superlattice layers, the surface cell magnetic barrier height is found to vary with spin orientation. Hence, each spin polarization involves different conditions of surface state existence. Our computations show a split of Shockley states into two levels (corresponding to different spin polarizations) and appearance of Tamm states (with specific spin polarization), induced by sufficiently strong magnetic fields. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Current induced switching due to spin‐transfer in spin valves: macroscopic model
Authors: Gmitra M. , Barnaś J. , Fert A. , Weymann I. , Dugaev V. K. 
Published: January 2006

AbstractWe develop a macroscopic description of current‐induced torque due to spin transfer in layered systems consisting of ferromagnetic films separated by a nonmagnetic layer. The description is based on the classical spin diffusion equations for the distribution functions inside the films used in the theory of CPP‐GMR, and macroscopic boundary conditions for the longitudinal and transverse components of the spin current. Due to strong exchange field in ferromagnetic films, we assume that the perpendicular component of spin current is totally absorbed within the narrow interface region giving rise to the torque. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Kondo effect in spin‐dependent transport through a quantum dot for a finite correlation parameter U
Authors: Wilczyński M. , Świrkowicz R. , Barnaś J. 
Published: January 2006

AbstractThe Kondo effect in a system consisting of a QD coupled to non‐magnetic or ferromagnetic electrodes is studied theoretically in the framework of the non‐equilibrium Green function formalism. Variation of the Kondo anomaly in differential conductance with the correlation parameter U is analyzed in detail. Splitting of the Kondo peak in an external magnetic field and/or due to an effective exchange field created by ferromagnetic electrodes is also discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin‐polarized resonant tunneling through two coupled quantum dots
Authors: Trocha P. , Barnaś J. 
Published: January 2006

AbstractResonant electronic transport through two coupled non‐interacting single‐level quantum dots attached to ferromagnetic leads with collinear magnetizations is analyzed theoretically. Coupling of the dots to external leads as well as the inter‐dot coupling are assumed to be spin dependent. Basic transport characteristics, including current‐voltage curves, linear and nonlinear conductance, and tunnel magnetoresistance associated with magnetization rotation are calculated using the Green function technique. The relevant Green functions have been calculated by the equation of motion method. Variation of the transport characteristics with such system parameters like energy level position, spin polarization of the leads, and coupling between the dots has been calculated numerically. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic anisotropy and resonance linewidth of Fe3Si/GaAs(001)
Authors: Lenz K. , Kosubek E. , Baberschke K. , Herfort J. , Schönherr H.‐P. , Ploog K. H. 
Published: January 2006

AbstractThe magnetic anisotropy energy and the resonance linewidth of epitaxial Fe3Si grown on GaAs(001) is studied by ferromagnetic resonance (FMR) technique. For a nearly stoichiometric sample (25.5% Si‐content) a clear fourfold anisotropy is observed which is modulated by a small contribution of an uniaxial in‐plane anisotropy. This uniaxial component is found to increase with the Fe concentration in the intermetallic compound. The samples show an exceptional narrow resonance linewidth of only 17 Oe at 9 GHz excitation frequency confirming the very high structural quality. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic studies of Fe(III)–crosslinked chitosan
Authors: Nedelko N. , Ślawska‐Waniewska A. , Kaźmierczak J. , Rodrigues C. A. , Bordini C. 
Published: January 2006

AbstractThe low‐temperature dc and ac magnetic measurements of Fe(III)–crosslinked chitosan complexes are reported. The results obtained indicate a complex magnetic structure in which strong antiferromagnetic interactions coexist with weak ferromagnetism. Fe‐chitosan exhibits features of a glassy state as well as canted antiferromagnetism and its low temperature collective magnetic behaviour can result from the coexistence of these two types of ordering. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)