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1 Apr 2012

Volume 111, Issue 7, Articles (07xxxx)

Issue Cover Spotlight Figure

J. Appl. Phys. 111, 071101 (2012); http://dx.doi.org/10.1063/1.3694674 (23 pages)

Shunfeng Li and Andreas Waag
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back to top Ultra-thin and Multi-layer Films

Ferromagnetic resonance probed annealing effects on magnetic anisotropy of perpendicular CoFeB/MgO bilayer

Y. S. Chen, Chih-Wei Cheng, G. Chern, W. F. Wu, and J. G. Lin

J. Appl. Phys. 111, 07C101 (2012); http://dx.doi.org/10.1063/1.3670042 (3 pages) | Cited 1 time

Online Publication Date: 3 February 2012

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The annealing effects of perpendicular MgO/CoFeB/Ta structure are investigated with ferromagnetic resonance technique. The data of angular dependent resonance field, linewidth, and intensity are obtained for both as-grown and annealed samples. An increment of magnetic out-of-plane anisotropy field from 1800 to 3300 Oe with annealing is observed, which should be related to the improvement of crystalline at the interface. Ferromagnetic resonance linewidth significantly broadens after annealing, and this broadening is attributed to the enhancement of inhomogeneity of the internal field.
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76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
75.60.Nt Magnetic annealing and temperature-hysteresis effects
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.30.Gw Magnetic anisotropy

Oscillatory magnetic anisotropy due to quantum well states in thin ferromagnetic films (invited)

M. Przybylski, M. Dąbrowski, U. Bauer, M. Cinal, and J. Kirschner

J. Appl. Phys. 111, 07C102 (2012); http://dx.doi.org/10.1063/1.3670498 (6 pages) | Cited 1 time

Online Publication Date: 7 February 2012

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Magnetic anisotropy depends strongly on the density of states at the Fermi level. If significant contributions to magnetocrystalline anisotropy energy (MAE) are due to spin-polarized quantum well states (QWS), a significant increase of MAE can occur periodically as a function of film thickness. The oscillation period L is determined by the wavelength of the corresponding electron waves. The uniaxial magnetic anisotropy of fcc-Co is found to oscillate with a period of 2.3 ML. In contrast, in bcc-Fe, the uniaxial magnetic anisotropy oscillates with a period of 5.9 ML. We attribute such oscillations to QWS in a minority-spin d-band at the Fermi level.
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75.30.Gw Magnetic anisotropy
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Cc Other ferromagnetic metals and alloys
73.20.At Surface states, band structure, electron density of states
71.20.Be Transition metals and alloys

Non-collinear magnetic profile in (Rh/Fe1−xCox)2/Rh(001) bilayer probed by polarized soft x-ray resonant magnetic reflectivity

M. Przybylski, J.-M. Tonnerre, F. Yildiz, H. C. N. Tolentino, and J. Kirschner

J. Appl. Phys. 111, 07C103 (2012); http://dx.doi.org/10.1063/1.3670507 (3 pages)

Online Publication Date: 8 February 2012

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Magnetization configuration in Fe/Rh/Fe0.5Co0.5/Rh(001) can be non-orthogonal due to competition between the anisotropy and the exchange coupling. Soft x-ray resonant magnetic reflectivity allows us to probe the magnetic profile along the growth axis with in-plane and perpendicular magnetization components. By using different modes of acquisition, we show that it is possible to determine separately the magnetic profile of both magnetization components. Measurements at the Co L3-edge enable us to investigate the magnetism of the alloy layer independently from the layer of Fe.
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75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Et Exchange and superexchange interactions

Surface morphologies and magnetic properties of Fe and Co magnetic thin films on polyethylene naphthalate organic substrates

Hideo Kaiju, Taro Abe, Kenji Kondo, and Akira Ishibashi

J. Appl. Phys. 111, 07C104 (2012); http://dx.doi.org/10.1063/1.3670609 (3 pages) | Cited 1 time

Online Publication Date: 9 February 2012

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We have studied the surface morphologies and magnetic properties of Fe and Co thin films evaporated on polyethylene naphthalate (PEN) organic substrates toward the fabrication of spin quantum cross devices. As a result, the surface roughnesses of Co (6.1 nm)/PEN and Co (12 nm)/PEN are as small as 0.1 and 0.09 nm, respectively, corresponding to less than one atomic layer, in the same scanning scale as the thickness. As for the magnetic properties, the coercive force of the Co/PEN shows the constant value of 2 kA/m upon decreasing the Co thickness from 35 to 10 nm, and it increases up to 7 kA/m upon decreasing the Co thickness from 10 to 5 nm. It decreases when the Co thickness is less than 5 nm. These results can be explained by the competition between the shape magnetic anisotropy and the induced magnetic anisotropy.
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75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
68.35.bd Metals and alloys
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Gw Magnetic anisotropy

Study of surface effects on CoCu nanogranular alloys by ferromagnetic resonance

A. García Prieto, M. L. Fdez-Gubieda, L. Lezama, and I. Orue

J. Appl. Phys. 111, 07C105 (2012); http://dx.doi.org/10.1063/1.3671073 (3 pages)

Online Publication Date: 13 February 2012

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Room temperature ferromagnetic resonance measurements have been performed on Co5 Cu95 melt-spun nanogranular alloys. Results on the ratio of the orbital-to-spin magnetic moment have been compared to previous results obtained by x-ray magnetic circular dichroism, explaining the differences in terms of the degree of magnetic saturation of the samples. Finally, the ferromagnetic resonance results have been related to the giant magnetoresistance (GMR) response of the samples at each stage of annealing, which has been interpreted as a sign of the interfacial origin of the GMR phenomenon.
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75.75.-c Magnetic properties of nanostructures
75.50.Tt Fine-particle systems; nanocrystalline materials
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
75.60.Nt Magnetic annealing and temperature-hysteresis effects
75.30.Cr Saturation moments and magnetic susceptibilities
75.47.De Giant magnetoresistance

Thermal stability of CoFeB/Pt multilayers with perpendicular magnetic anisotropy

Yanyan Zhu, Zongzhi Zhang, Bin Ma, and Q. Y. Jin

J. Appl. Phys. 111, 07C106 (2012); http://dx.doi.org/10.1063/1.3671776 (3 pages)

Online Publication Date: 14 February 2012

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The perpendicular anisotropy and thermal stability of [CoFeB/Pt]5 multilayers are investigated with various CoFeB thicknesses (tCoFeB) and a fixed Pt thickness of 10.0 Å. Magnetic hysteresis loops exhibit a square shape for 2.2–4.0Å tCoFeB and suggest that multilayers with appropriate CoFeB and Pt thicknesses display perpendicular magnetic anisotropy (PMA). After post-deposition annealing at temperatures of Ta < 300 °C, no obvious change occurs in the loop shape for tCoFeB = 2.2 Å, while the perpendicular coercivity increases with increasing Ta for the sample with tCoFeB = 4.5 Å due to the enhanced (111) texture. At Ta ∼ 300 °C, the original square loops for both samples start to tilt, showing that the occurrence of the PMA degradation is independent of the CoFeB thickness. The XRD results indicate that the observed decay of the PMA in CoFeB/Pt multilayers upon postannealing is associated with the interdiffusion and alloying effects at the CoFeB/Pt interfaces.
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75.30.Gw Magnetic anisotropy
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
81.40.Gh Other heat and thermomechanical treatments
66.30.Ny Chemical interdiffusion; diffusion barriers

Strain-induced magnetoresistance and magnetic anisotropy properties of Co/Cu multilayers

C. Rizal, P. Gyawali, I. Kshattry, and R. K. Pokharel

J. Appl. Phys. 111, 07C107 (2012); http://dx.doi.org/10.1063/1.3671788 (3 pages) | Cited 2 times

Online Publication Date: 15 February 2012

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[Co (tCo) nm/Cu 1.5 nm]50 multilayers were grown onto 15-nm Cu/polyimide buffer layers. The relationship between stress, σ, and strain, ɛ, for the [Co 1.0 nm/Cu 1.5 nm]50 multilayers has been presented. The effects of induced strain on the magnetoresistance (MR) and magnetic anisotropy have been examined. The [Co 1.0 nm/Cu 1.5 nm]50 multilayer exhibited a maximum MR ratio of 3.4% at a Co layer thickness of 1.0 nm, β of 0.1, and a strain of 1.5%. The multilayers exhibited a remarkable magnetic anisotropy with the easy axis of magnetization always lying in a plane perpendicular to the direction of the induced strain.
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75.30.Gw Magnetic anisotropy
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
81.40.Gh Other heat and thermomechanical treatments
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.F- Deformation and plasticity
72.15.Gd Galvanomagnetic and other magnetotransport effects

Magnetic properties of ultrathin single crystal Fe3O4 film on InAs(100) by ferromagnetic resonance

Z. C. Huang, X. F. Hu, Y. X. Xu, Y. Zhai, Y. B. Xu, J. Wu, and H. R. Zhai

J. Appl. Phys. 111, 07C108 (2012); http://dx.doi.org/10.1063/1.3677673 (3 pages)

Online Publication Date: 23 February 2012

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The evolution of both in-plane and out-of-plane magnetic anisotropies has been studied on different thicknesses of Fe3O4/InAs(100) hybrid spintronic structures by ferromagnetic resonance. The uniaxial magnetic anisotropy with easy axis along InAs [011] direction and hard axis along [0-11] direction and the cubic magnetic anisotropy are determined by fitting the resonance field. The cubic magnetic anisotropy constant K1 is negative, as that of bulk magnetite, and its absolute value increases rapidly from 0.2 × 104 erg/cm3 to 10.8 × 104 erg/cm3 with increasing thickness of Fe3O4 film. When the thickness of Fe3O4 film is only several monolayers (tFe = 6 nm), a bulk-like cubic magneto-crystalline anisotropy is built up. The uniaxial anisotropy constant is much smaller than that in Fe3O4/GaAs film with the same thickness of Fe3O4 film, as expected from the less lattice mismatch at the interface.
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75.70.Ak Magnetic properties of monolayers and thin films
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
75.30.Gw Magnetic anisotropy

The thickness, electric field, and strain effects on the magnetic anisotropy of FeCo/MgO(001) thin films: A first principles study

K. H. He and J. S. Chen

J. Appl. Phys. 111, 07C109 (2012); http://dx.doi.org/10.1063/1.3672855 (3 pages) | Cited 1 time

Online Publication Date: 24 February 2012

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The magnetic anisotropy of the FeCo/MgO(001) thin films with the effects of thickness, the electric field, and the strain of the in-plane lattice constant were investigated by first-principles calculations. The thickness dependence of the magnetic anisotropy of FeCo ultrathin films in the range of one to four monolayers was explored, and the films with one, three, and four FeCo monolayers preferred the in-plane easy axis of magnetization, while the film with two FeCo monolayers occupied the perpendicular anisotropy. In the presence of an electric field, the magnetic anisotropy energies for all four films could be enhanced; moreover, the transition of the easy axis of magnetization from in-plane to out-of-plane also could be obtained, and the transition electric field was related with their thickness. It could be found that the variation of the in-plane lattice constant resulted in the switching from the perpendicular to in-plane anisotropy for the film with two FeCo monolayers.
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75.70.Ak Magnetic properties of monolayers and thin films
75.30.Gw Magnetic anisotropy
75.50.Bb Fe and its alloys
75.40.Mg Numerical simulation studies
68.55.jd Thickness

Effect of the number of interfaces on the magnetic properties of [SnO2/Cu-Zn ferrite] multilayer

S. Saipriya, Joji Kurian, and R. Singh

J. Appl. Phys. 111, 07C110 (2012); http://dx.doi.org/10.1063/1.3673406 (3 pages)

Online Publication Date: 27 February 2012

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The [SnO2/Cu-Zn ferrite (CZF)]n (n = 5, 10, 15, and 20) multilayer (ML) were deposited by rf-magnetron sputtering to study their magnetic properties. The magnetization and ferromagnetic resonance (FMR) measurements were undertaken to understand the effect of interfaces on the magnetic properties of these ML. FMR signal line shape changes from asymmetric to symmetric as n increases. The FMR signal peak to peak intensity, FMR linewidth, effective and saturation magnetization and coercivity exhibit oscillations as a function of n. In the parallel configuration the resonance field increases with increase in n, presumably due to the decrease in the active layer to dead layer thickness ratio. The interlayer coupling is strong in the ML with n = 5 leading to the formation of spin waves. The ML interlayer coupling and anisotropy decreases with increasing n. The oscillatory behavior of the magnetic properties can be ascribed to the nonmonotonic variations in the structure and the geometry of the interfaces.
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75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
81.15.Cd Deposition by sputtering
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
75.30.Gw Magnetic anisotropy
75.50.Gg Ferrimagnetics

Effect of thickness of MgO, Co-Fe-B, and Ta layers on perpendicular magnetic anisotropy of [Ta/Co60Fe20B20/MgO]5 multilayered films

Fu-Te Yuan, Yi-Hung Lin, J. K. Mei, Jen-Hwa Hsu, and P. C. Kuo

J. Appl. Phys. 111, 07C111 (2012); http://dx.doi.org/10.1063/1.3673408 (3 pages) | Cited 2 times

Online Publication Date: 27 February 2012

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This study elucidates the magnetic properties of [Ta/Co60Fe20B20/MgO]5 as functions of thickness of each layer. Its perpendicular magnetic anisotropy (PMA) is found to depend strongly on the thickness of the MgO (tMgO) and Co-Fe-B (tCoFeB) layers. The Ta/CoFeB interface is critical to inducing PMA. A maximum room-temperature (RT) anisotropic energy (KuRT) of about 1 × 106 erg/cm3 and an anisotropic field (HkRT) of 4.7 kOe are obtained in the RT-prepared multilayered sample with tMgO = 1.0, tCoFeB = 1.3, and thickness of layer tTa = 10 nm. These values are comparable to the published values for Co60Fe20B20 after optimized field annealing. In this investigation, post-annealing has a more complicated effect on PMA in a multilayered structure than in a single or a double Co-Fe-B layer, both of which structure have been examined elsewhere. This result may be explained by the competing effects of the thermal process, which is an improvement of the crystallinity of Co-Fe-B and roughening of the interface.
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75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
68.65.Ac Multilayers
75.70.Ak Magnetic properties of monolayers and thin films
75.30.Gw Magnetic anisotropy
81.40.Gh Other heat and thermomechanical treatments
68.35.Ct Interface structure and roughness

Promotion of L10 ordering of FePd films with amorphous CoFeB thin interlayer

M. N. I. Khan, N. Inami, H. Naganuma, Y. Ohdaira, M. Oogane, and Y. Ando

J. Appl. Phys. 111, 07C112 (2012); http://dx.doi.org/10.1063/1.3673409 (3 pages) | Cited 1 time

Online Publication Date: 27 February 2012

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The L10-ordered FePd thin films were prepared using an ultrahigh vacuum magnetron sputtering system on MgO(001) substrates at 300 °C. The crystallographic and magnetic properties and the surface morphology of films with and without a very thin amorphous CoFeB intermediate layer inserted between the FePd and the MgO layers were systematically investigated as a function of the thickness of the FePd layer. The perpendicular anisotropy of the samples was increased by inserting the thin CoFeB as an intermediate layer below the FePd with a thickness of 4.0 nm. The reason for the enhancement by inserting the amorphous CoFeB layer is attributed to: (i) the promotion of the L10 ordering of the FePd due to the reduction of the lattice mismatch between the MgO and FePd, and (ii) the fact that thin CoFeB has a perpendicular anisotropy at the interface of the MgO, which superposed the perpendicular anisotropy of the L10-FePd.
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75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
81.15.Cd Deposition by sputtering
68.55.aj Insulators
75.30.Gw Magnetic anisotropy
75.50.Kj Amorphous and quasicrystalline magnetic materials

Perpendicular magnetic anisotropy of Ni/Cu(001) films with surface passivation

Wei Pan, Ying-Ta Shih, Kuo-Long Lee, Wen-He Shen, Chung-Wei Tsai, Der-Hsin Wei, Yuet-Loy Chan, and Hui-Ching Chang

J. Appl. Phys. 111, 07C113 (2012); http://dx.doi.org/10.1063/1.3676227 (3 pages) | Cited 2 times

Online Publication Date: 5 March 2012

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A 13 monolayer Ni film was deposited on Cu(001) and followed by oxygen exposure at 300 K. It was confirmed that the surface contained Ni oxide with an amorphous atomic arrangement. The magnetization is perpendicular after surface oxidation. The coercivity is substantially enhanced without shifting of the hysteresis loop after field cooling. This could indicate that the NiO is randomly antiferromagnetic or that the Neél temperature of the NiO is above 300 K. This surface oxide leads to surface passivation so that the film is magnetically alive under ambient conditions, which could have useful applications in the future.
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75.70.Ak Magnetic properties of monolayers and thin films
75.70.Rf Surface magnetism
75.30.Gw Magnetic anisotropy
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.50.Ee Antiferromagnetics
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects

Energy-level alignment at the Alq3/Fe3O4(001) interface

A. Pratt, L. Dunne, X. Sun, M. Kurahashi, and Y. Yamauchi

J. Appl. Phys. 111, 07C114 (2012); http://dx.doi.org/10.1063/1.3677768 (3 pages)

Online Publication Date: 8 March 2012

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We have used the technique of metastable de-excitation spectroscopy to probe the interfacial electronic structure of the organic semiconductor (OSC) Alq3 deposited onto clean Fe3O4(001) substrates. We have measured shifts in the low-energy secondary electron cutoff and energetic onset of the highest occupied molecular orbital (HOMO) of Alq3 as the coverage increases from the sub-ML range to multilayer formation. We find that the presence of an interfacial dipole induces a uniform decrease in the valence band electronic states by 1.2 eV with respect to the vacuum level and modifies the position of the HOMO energetic onset to 1.8 eV below the substrate Fermi level. The strong intrinsic dipole moment of Alq3 is suggested as the origin for these changes in accordance with previous studies of Alq3 deposited onto various substrates.
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71.20.Rv Polymers and organic compounds
72.25.-b Spin polarized transport
73.20.At Surface states, band structure, electron density of states

Interface magnetism of iron grown on sulfur and hydrogen passivated GaAs(001)

B. Kardasz, S. P. Watkins, E. A. Montoya, C. Burrowes, E. Girt, and B. Heinrich

J. Appl. Phys. 111, 07C115 (2012); http://dx.doi.org/10.1063/1.3677822 (3 pages)

Online Publication Date: 8 March 2012

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Sulfur (S) and hydrogen (H) atom passivated GaAs(001) templates were used for deposition of ultrathin crystalline Fe films using molecular beam epitaxy, where the Fe thickness ranged from 10 to 45 atomic layers. Reflection high-energy electron diffraction patterns showed that the S- and H-passivated surfaces had no and very weak (1 × 2) superlattice reconstructions, respectively. This indicates that these GaAs(001) templates have a square-like symmetry. Magnetic anisotropies were investigated using the in-plane angular dependence of ferromagnetic resonance at 36 GHz. The in-plane cubic and uniaxial anisotropies and perpendicular uniaxial field were described by bulk and interface contributions, indicating that the Fe films have a high lattice coherence. The magnetic properties of the Fe films were compared to those grown on more commonly used GaAs(001) templates having a (4 × 6) reconstruction with an As-rich in-plane uniaxial symmetry. The Fe films grown on S-passivated templates exhibited unique magnetic properties caused by a decreased lattice spacing compared to the bulk Fe.
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75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
76.50.+g Ferromagnetic, antiferromagnetic, and ferrimagnetic resonances; spin-wave resonance
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
75.30.Gw Magnetic anisotropy
75.50.Bb Fe and its alloys
75.70.Ak Magnetic properties of monolayers and thin films

The concept and fabrication of exchange switchable trilayer of FePt/FeRh/FeCo with reduced switching field

T. J. Zhou, K. Cher, J. F. Hu, Z. M. Yuan, and B. Liu

J. Appl. Phys. 111, 07C116 (2012); http://dx.doi.org/10.1063/1.3677838 (3 pages)

Online Publication Date: 8 March 2012

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We report the concept and fabrication of exchange switchable trilayer of FePt/FeRh/FeCo with reduced switching field for heat assisted magnetic recording (HAMR). A thin layer of FeRh is sandwiched between L10 FePt and magnetically soft FeCo. At room temperature, FePt and FeCo are magnetically isolated by the antiferromagnetic FeRh layer. After the metamagnetic transition of FeRh layer by heating, FePt and FeCo are exchange-coupled together through ferromagnetic FeRh layer. Therefore, the switching field of FePt can be greatly reduced via exchange-spring effect. Simulation work was carried out to understand the exchange coupling strength and the FeCo thickness effects on the switching field reduction. It is found that switching field decreases with the increase of exchange coupling strength and FeCo thickness. The trilayer films were also successfully fabricated. A clear change of reversal mechanism from two-step to one-step switching upon heating was observed and a 3-time switching field reduction was demonstrated. The results show the promise of the trilayer for HAMR applications.
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75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
81.40.Gh Other heat and thermomechanical treatments
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.50.Bb Fe and its alloys
75.50.Ee Antiferromagnetics
75.50.Ss Magnetic recording materials

Influence of ion beam assisted deposition parameters on the growth of MgO and CoFeB

Ricardo Ferreira, Susana Cardoso, Paulo P. Freitas, Rumyana Petrova, and Stephen McVitie

J. Appl. Phys. 111, 07C117 (2012); http://dx.doi.org/10.1063/1.3678319 (3 pages) | Cited 1 time

Online Publication Date: 9 March 2012

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The effect of the kinetic parameters of an assistance ion beam on the crystallization of ion beam deposited MgO was investigated. It is shown that the crystallization of MgO in the as-deposited state is strongly dependent on the assistance beam parameters. Furthermore, two deposition regimes corresponding to different ranges of the assistance beam energy are found. XRD and TEM studies of CoFeB/MgO/CoFeB with MgO deposited in the two regimes show that CoFeB crystallization is favored when low energy assist beams are used, despite no differences being found in the MgO.
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81.15.Jj Ion and electron beam-assisted deposition; ion plating
81.40.Gh Other heat and thermomechanical treatments
64.70.dg Crystallization of specific substances
68.55.at Other materials
61.80.Jh Ion radiation effects

Magnetism and structure of anatase (Ti1−xVx)O2 films

D. Le Roy, S. Valloppilly, R. Skomski, S.-H. Liou, and D. J. Sellmyer

J. Appl. Phys. 111, 07C118 (2012); http://dx.doi.org/10.1063/1.3679434 (3 pages)

Online Publication Date: 12 March 2012

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Anatase TiO2 is known as a promising host material for a wide-gap ferromagnetic semiconductor as it is a good solvent for numerous transition-metal elements. We report on the structural and magnetic properties of epitaxially grown anatase (Ti1−xVx)O2 layers where x covers the whole range of solubility of V atoms in anatase TiO2 and beyond the solubility limit of 21%. We measured an average magnetic moment per vanadium as high as 1 µB with a magnetic percolation threshold of less than 6% which agrees with recent theoretical predictions. Interestingly, our results show a decrease of the average V magnetic moment as x increases throughout the solubility range. Anatase (Ti1−xVx)O2 is no longer present beyond the solubility limit, where the nonmagnetic VO2 phase forms and destroys the net magnetization.
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75.70.Ak Magnetic properties of monolayers and thin films
64.75.Bc Solubility
75.30.Cr Saturation moments and magnetic susceptibilities
75.50.Pp Magnetic semiconductors

Magnetic anisotropy and magnetization reversal in Co/Cu multilayers nanowires

Naeem Ahmad, J. Y. Chen, D. W. Shi, Javed Iqbal, and Xiufeng Han

J. Appl. Phys. 111, 07C119 (2012); http://dx.doi.org/10.1063/1.3679862 (3 pages) | Cited 1 time

Online Publication Date: 13 March 2012

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The Co/Cu multilayer nanowires fabricated in an array using anodized aluminum oxide (AAO) template by electrodeposition method, have been investigated. It has been observed that the magnetization reversal mode and magnetic anisotropy depend upon the Co and Cu layer thicknesses. Magnetization reversal occurs by curling mode at around Co = 400 nm and Cu = 10 nm, while for Co = 30 nm and Cu = 60 nm, magnetization reversal occurs by nucleation mode. A change of magnetic anisotropy from out of plane to in plane is observed when thickness of Cu layer tCu = 60 nm and that of Co tCo = 30 nm. Magnetic anisotropy is lost when thickness of the Co layer tCo = 400 nm and that of Cu tCu= 10 nm. Magnetic properties have been explained by the competition among shape anisotropy, magnetostatic interactions and magnetocrystalline anisotropy. Magnetic properties can be tuned accordingly depending upon the thickness of the Co and Cu nanodisks.
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75.30.Gw Magnetic anisotropy
75.60.Jk Magnetization reversal mechanisms
75.75.Cd Fabrication of magnetic nanostructures
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
81.15.Pq Electrodeposition, electroplating

Investigation of spin and orbital moments of L10 FePtRh thin films

D. B. Xu, C. J. Sun, J. S. Chen, S.-W. Han, S. M. Heald, R. A. Rosenberg, and G. M. Chow

J. Appl. Phys. 111, 07C120 (2012); http://dx.doi.org/10.1063/1.3680542 (3 pages)

Online Publication Date: 14 March 2012

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Fe50Pt50−xRhx films have attracted much interest recently due to their potential usage in heat assisted magnetic recording media and the ferromagnetic (FM) to antiferromagnetic (AFM) transition as Rh concentration is increased. In this study, we present an investigation of the spin moment (ms) and orbital moment (ml) of Fe in Fe50Pt50−xRhx films using x-ray magnetic circular dichroism. The measurements were made in the soft x-ray region along the film normal, which corresponds to the easy axis of the (001) textured L10 FePt with uni-axial magnetic anisotropy. They show that the magnetic moment of Fe mainly contributes to the whole magnetization of the films. The decrease of ml with Rh doping concentration implies a decrease of magneto-crystalline anisotropy, whereas the significant decrease of ms is consistent with the FM to AFM transition at above 15 at. % of Rh.
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75.30.Cr Saturation moments and magnetic susceptibilities
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.50.Bb Fe and its alloys
75.50.Ss Magnetic recording materials
75.70.Ak Magnetic properties of monolayers and thin films
78.20.Ls Magneto-optical effects
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