The occurrence of ferro - and antiferromagnetism in Mn-Ni-Al alloys is governed by the sign of the direct exchange interaction between the Mn magnetic ions. Experimentally has been found that, if the separation between the Mn magnetic ions is greater than the critical value dcr= 2.91 Å, they are ferromagnetic and if the distance is less than the critical value, they are antiferromagnetic. The value of Mn local magnetic moment depends on the number of Al atoms in the first vicinity but the dominant factor is the Mn-Al distance. The nature of Mn-Mn exchange coupling was studied through X-ray diffraction, magnetic and XPS measurements.

Experimental and theoretical investigations on the structural and magnetic properties of the MnBi and MnBiC hard magnetic phases are presented. X-ray diffraction patterns showed that the highest concentration of MnBi low-temperature phase (LTP) was obtained for annealing at 400 ?C for 12 h. X-ray photoemission measurements (XPS) of the core levels (Mn 2p and 3d; Bi 4d and 5p, respectively) show chemical shifts by C addition, providing evidence that the C atoms enter the MnBi structure in the vicinity of both type of metallic atoms. C atoms were assumed to occupy the 2d interstitial crystal sites of the hexagonal NiAs structure type, as suggested in earlier studies. The theoretical calculations show that C addition enhances slightly the magnetic moment of the samples compared to pristine LTP MnBi, in agreement with our magnetic measurements. Also, following both theoretical and experimental investigations, we obtained increased magnetocrystalline anisotropy energy (MAE) by adding C as interstitial dopant.

Detailed theoretical and experimental investigations on the electronic and magnetic properties of the Mn2Co1-xVxAl Heusler compounds are presented. The magnetization vs. temperature measurements on the Mn2Co1-xVxAl Heusler compounds show a decrease of the Curie temperature with V content, between 745 K (x = 0) and 671 K (x = 0.5). Ferrimagnetic near fully compensated behaviour with the saturation magnetization of 0.29 mu(B)/f.u. has been obtained experimentally for Mn2Co0.5V0.5Al alloy, in slight disagreement with Slater-Pauling rule. The electronic band structure calculations performed using the Korringa-Kohn-Rostoker (KKR) Green's function method for the Mn2Co0.5V0.5Al alloy show half-metallic almost compensated ferrimagnetic behaviour with total spin moment of 0.02 mu(B)/f.u.. Accounting for the preferential site occupation determined by total energy calculations results an increase of the calculated spin moment, in agreement with the magnetic measurements. The fully compensated ferrimagnetic behaviour is predicted theoretically for the compounds derived from Mn2Co0.5V0.5Al by slight variation on composition. The half-metallic character deduced from density of states (DOS) calculations is expected to be preserved for the stoichiometric and off-stoichiometric alloys.

The structural, electronic and magnetic behavior of the as-cast and annealed Mn52Al46Ti2 and Mn50Al46Ti4 alloys have been studied through electronic band structure calculations, X-ray diffraction and magnetic measurements in the temperature range 4-850 K and magnetic field up to 7 T. Band structure calculations show a preference for Ti atoms to occupy the Mn sites in the plane of Al atoms with their magnetic moments (similar to 0.68 mu(B)/Ti) coupled antiparallel relative to the Mn magnetic moments in the plane of Mn atoms (2.33 mu(B)/Mn). The as-cast and annealed samples were phase mixtures with different values of the hard ferromagnetic tau phase content. Except the as-cast and annealed at 1050 degrees C Mn52Al46Ti2 alloys, all the analyzed samples include, along with the tau and gamma 2 phases, a soft kappa phase (CsCl - structure type) with T-C around 530 K. The best magnetic characteristics were obtained for Mn52Al46Ti2 alloy annealed at 470 degrees C for 6 h: M-S = 116 A m(2)/Kg at 4 K and T-C = 668 K, in good agreement with the values reported in the literature for the t phase of the MnAl system. The effects of the composition and of the preparation route on the electronic and magnetic properties are discussed in comparison with the properties of Mn54Al46 parent alloy. (C) 2016 Elsevier Ltd. All rights reserved.

The magnetic properties of CeCoMn, Ce3Co3Mn4 and Ce3Co6Mn alloys have been investigated by magnetization and susceptibility measurements in the temperature range (5 300) K and magnetic eld up to 12 T. X-ray powder di raction measurements showed that all three alloys are isostructural and crystallize in the cubic MgCu2 structure type. Both Ce and Co atoms are non-magnetic in all alloys like in the isostructural compound CeCo2. Magnetic behavior of the investigated alloys is mostly due to the Mn moments and depends essentially on the Mn Mn distances. The interaction between the Mn moments is antiferromagnetic in CeCoMn and Ce3Co3Mn4 but a paramagnetic behavior for Ce3Co6Mn was evidenced in the studied temperature range.

The magnetic properties of CeCoMn, Ce3Co3Mn4 and Ce3Co6Mn alloys have been investigated by magnetization and susceptibility measurements in the temperature range (5-300) K and magnetic field up to 12 T. X-ray powder diffraction measurements showed that all three alloys are isostructural and crystallize in the cubic MgCu2 structure type. Both Ce and Co atoms are non-magnetic in all alloys like in the isostructural compound CeCo2. Magnetic behavior of the investigated alloys is mostly due to the Mn moments and depends essentially on the Mn Mn distances. The interaction between the Mn moments is antiferromagnetic in CeCoMn and Ce3Co3Mn4 but a paramagnetic behavior for Ce3Co6Mn was evidenced in the studied temperature range.

The electronic properties of RCo5−xMx (R=Er, Sm, Tm; M=Si, Ga, Al; x=0 and 1) compounds were investigated by X-ray photoelectron spectroscopy (XPS). The study was focused on the Co 3s exchange splitting, the valence bands and chemical shifts of the elements from the analyzed compounds. The Co 2p3/2 core-level chemical shifts were described by means of the Auger parameters and Wagner plot. The hybridization between the R 5d6s and M 3sp and 4sp states and Co 3d states leads to a partial filling of the Co 3d band and to a decrease of the Co magnetic moments in comparison with the value in pure Co metal, in good agreement with the magnetic measurements.

The magnetic properties of CeCo7Mn5 and CeCo8Mn4 compounds have been investigated by combining X-ray photoelectron spectroscopy (XPS) and magnetic measurements in a wide temperature range (4-550) K and magnetic field up to 12 T. X-ray powder diffraction (XRD) measurements showed that CeCo7Mn5 and CeCo8Mn4 compounds are isostructural and crystallize in the ThMn12 structure type. XPS spectra pointed out the intermediate valence state of Ce atoms and that both Co and Mn atoms carry magnetic moments. The complex magnetic structure of CeCo7Mn5 and CeCo8Mn4 is determined by the competition between the ferromagnetic (Co-Co pairs) and antiferromagnetic (Co-Mn and Mn-Mn pairs) interactions. Two different ordering temperatures T-N and T-C correlated to antiferromagnetic and ferromagnetic coupling of 3d magnetic moments, respectively, are evidenced. Magnetic moments of about 1.6 mu(B)/Co and 3.2 mu(B)/Mn atoms were determined by correlating the magnetic data of the two compounds, in good agreement with the exchange splitting of XPS Co 3s and Mn 3s core levels. (c) 2013 Elsevier Ltd. All rights reserved.

The magnetic properties of the Ce2Co15Mn3 compound has been investigated combining X-ray photoelectron spectroscopy (XPS) and magnetic measurements in the temperature range (4-850) K and magnetic field up to 10 T. X-ray powder diffraction (XRD) measurements showed that Ce2Co15Mn3 compound crystallizes in the Th2Zn17 structure type. XPS spectra pointed out the intermediate valence state of Ce ions and that both Co and Mn atoms carry magnetic moments. The compound Ce2Co15Mn3 has a ferromagnetic behavior below the Curie temperature T-C = 740 K with a saturation magnetization at 4 K of 22.7 mu B/f.u. The magnetic structure in Ce2Co15Mn3 is determined by the competition between the ferromagnetic (Co-Co, the dominant one) and antiferromagnetic (Co-Mn and Mn-Mn pairs) interactions. (C) 2012 Elsevier B.V. All rights reserved.

XPS, magnetization and magnetic susceptibility measurements of Ni1-xMnxAl (x = 0.0, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8) alloys are reported. X-ray diffraction measurements showed that all investigated alloys are single phases with the same CsCl structure type. The hybridization between Al 3sp and Ni 3d states and Al 3sp and Mn 3d states leads to a partial filling of the Ni and Mn 3d bands. Like in the parent compound NiAl, the Anderson condition for the existence of a local magnetic moment on Ni site in Ni1-xMnxAl is not fulfilled. The contribution of Ni atoms to the measured magnetic susceptibility may be explained in the frame of the self-consistent renormalization theory of spin fluctuations. The ferromagnetic behaviour of the Ni1-xMnxAl alloys (x>0) is due to the interaction of local magnetic moments confined on Mn sites. The correlation between the magnetic results in the ordered and paramagnetic state indicates the presence of a number of antiferromagnetically coupled Mn-Mn pairs.

X-ray Diraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM) and magnetic measurements as a function of applied magnetic field and temperature for In1 xMnxSb (0.056 x 60.2) system are reported. Magnetic measurements performed at high and small magnetic field in ZFC and FC indicate the coexistence of ferromagnetic In1 xMnxSb solid solution and two types of magnetic cluster: ferromagnetic MnSb and ferrimagnetic Mn2Sb. XPS valence band and Mn 2p core level spectra have confirmed the presence of MnSb and Mn2Sb phases. TEM images show some manganese antimonide phase microinclusions with dimension between (30-40) nm.

X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), magnetization and magnetic susceptibility of Mn1−xAlxNi alloys are reported. A change in the crystallographic structure takes place around x=0.4 from CuAuI to CsCl (B2) structure type. For x0.5 a mixed B2+L21 state exists which incorporates antiferromagnetic (B2) and ferromagnetic (L21) parts. A direct evidence for the existence of local moments on Mn sites in Mn1-xAlxNi alloys is given by the exchange splitting of XPS Mn 3s and Mn 2p3/2 core levels. The gradual filling of the Ni 3d band as the Al concentration increases can be explained by the hybridization of the Ni 3d band and Al 3sp states.

The electronic and magnetic properties of AlDyNi, AlDyNi4 and AlDy3Ni8 are studied using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), static and dynamic magnetic measurements. The three compounds AlDyNi, AlDyNi4 and AlDy3Ni8 are single phases and crystallize in the Fe2P, CaCu5 and CeNi3 structure types, respectively. All the investigated compounds order ferromagnetically below the corresponding Curie temperatures. The Curie temperature and the magnetic moments are 25 K and 6 μB/f.u. for AlDyNi, 14 K and 6.9 μB/f.u. for AlDyNi4 and 22K and 19.2 μB/f.u. for AlDy3Ni8. At high temperature the magnetic susceptibility obey the Curie-Weiss law. The paramagnetic Curie temperature and the effective magnetic moments are 30K and 10.88 μB/f.u. for AlDyNi, 28 K and 10.94 μB/f.u. for AlDyNi4 and 18 K and 18.33 μB/f.u. for AlDy3Ni8. XPS valence band and Ni 2p spectra indicated the presence of small magnetic moment on Ni sites in AlDy3Ni8 and AlDyNi4, and a complete filling of Ni 3d band in AlDyNi.

The synthesis, X‐ray photoelectron spectroscopy (XPS), Raman spectroscopy. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) of Ni isolated single domain particles, obtained from powdered CeNi5 oxidized in air at different temperatures up to 800°C, are reported.

X-ray photoelectron spectroscopy (XPS), magnetization and magnetic susceptibility of Mn1-xAlxNi3 (x=0.5, 0.7) alloys are reported. The Ni 2p core level and the valence band spectra of AlMnNi6 equivalent to Al0.5Mn0.5Ni3 and Al7Mn3Ni30 equivalent to Al0.7Mn0.3Ni3 exhibit satellites at similar to 6.5 eV higher binding energy than the main line, indicating the presence of d character in the unoccupied bands. Furthermore, the density of states at the Fermi level in both alloys is smaller than in the metallic Ni, suggesting a partial filling of the Ni 3d band. The magnetization values and its variation with magnetic field and temperature suggest that both alloys have a ferromagnetic behavior below the Curie temperatures 432 K and 361 K for AlMnNi6 and Al7Mn3Ni30, respectively. The results infer the existence of local magnetic moments on Mn and Ni sites in the investigated alloys. The correlation of magnetic data in the ordered and paramagnetic states can be explained if we consider spin fluctuations on Ni sites.

X‐ray photoelectron spectroscopy, magnetization and magnetic susceptibility of MnPd1–x Sbx are reported. The substitution of Pd by Sb leads to drastic changes both in the crystallographic and electronic structure, with remarkably modifications in the magnetic properties of the investigated systems. The most important feature of the XPS spectra is the well‐defined magnetic exchange splitting of the Mn 3s core levels of all investigated alloys, giving a direct evidence of the existence of local magnetic moments in the Anderson's sense confined on Mn sites. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)