Ramanathan Krishnan

Ramanathan Krishnan
French National Centre for Scientific Research | CNRS

Doctor of Science

About

468
Publications
57,673
Reads
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4,726
Citations
Additional affiliations
January 1994 - August 1997
Versailles Saint-Quentin-en-Yvelines University
Position
  • Directeur de Recherche
Description
  • I have retired in 1997.
January 2001 - December 2004
Université Hassan II Casablanca
Description
  • Collaboration.
January 1982 - present
Indian Institute of Technology Bombay
Description
  • This is a collaborative project between our laboratory and IITB. Working with the group of Prof.Shiva Prasad & Prof. N.Venkatramani of Metallurgy Dept.
Education
November 1960 - July 1964
University of Paris-Sud
Field of study
  • Magnetism in ferrimagnetic crystals.

Publications

Publications (468)
Article
In this paper, we report our observation of an extraordinarily large value of magnetization in an annealed CoFe2O4/ZnFe2O4 bilayer. Sets of bilayers of CoFe2O4/ZnFe2O4 were deposited at ambient temperature, using pulsed laser deposition setup equipped with Nd: YAG laser, and subsequently annealed in air at different temperatures for 2h. The highest...
Article
We report the effect of substitution of 10% divalent ion (Mn²⁺, Co²⁺ and Ni²⁺) on the magnetization of Zn ferrite thin films. M0.1Zn0.9Fe2O4 (M = Mn²⁺, Co²⁺ and Ni²⁺) thin films were pulse laser deposited on to fused quartz substrate at substrate temperatures (TS) ranging from room temperature (RT) to 750 °C. Some of the films deposited with substr...
Article
Mn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</sub> Zn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w...
Article
The magnetoelastic properties of nano-crystalline zinc ferrite (ZnFe2O4) thin films prepared by Pulse laser deposition on amorphous fused quartz substrates have been investigated by means of the strain-modulated ferromagnetic resonance, as a function of the substrate temperature during the deposition, and as a function of the annealing temperature....
Article
Full-text available
Single phase nano-crystalline zinc ferrite (ZnFe2O4) thin films were deposited on fused quartz substrate using the pulsed laser deposition technique. The films were deposited at different substrate temperatures. The field dependence of magnetization at 10 K shows hysteresis loops for all the samples. Temperature dependence of the field cooled (FC)...
Article
Full-text available
MnFe2O4 thin films were pulsed laser deposited on to quartz substrate from room temperature (RT) to 650 °C in a pure argon environment. Temperature dependence of spontaneous magnetization (4πMS) was measured on these films from 10 K to 350 K using a vibrating sample magnetometer. Ferromagnetic resonance (FMR) study was also carried out at 300 K. Th...
Article
Full-text available
Co0.3Zn0.7Fe2O4 nanocrystalline thin films were deposited by pulsed laser ablation technique on amorphous quartz substrate. These films were as deposited at different substrate temperatures (TS) varying from room temperature (RT) to 750 °C. The RT deposited films were ex situ annealed at annealing temperatures (TA) ranging from 150 °C to 750 °C. Th...
Article
The magnetic properties of pulsed laser deposited Co-Zn ferrite [Co1-xZnxFe2O4 (0.1≤x≤0.7)] nanocrystalline thin films have been investigated. The films were deposited on amorphous quartz substrate. The observed magnetic properties of the films depend on the deposition temperature (TS), the annealing temperature (TA) and the Zn content (x). A magne...
Article
Nano-crystalline magnetic ZnFe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> thin films were deposited in oxygen atmosphere at different substrate temperatures (T <sub xmlns:mml="http://ww...
Article
Full-text available
Zinc ferrite thin films of varying thickness were deposited at ambient temperature using RF-magnetron sputtering. The films were annealed at temperatures in the range 250 °C to 650 °C in air for 2 hrs. The magnetization of the film was observed to depend on the average grain size and also on thickness of the film. It was found that thermal annealin...
Article
Full-text available
Single phase nano-crystalline zinc ferritethin films were deposited by RF-magnetron sputtering on quartz substrate at room temperature (RT) in pure Argon environment and annealed (in air) at different temperatures.Temperature dependence of magnetization was studied on these films using both VSM and by observing FMR (in X band). Value of exchange st...
Article
Zinc ferrite films were deposited on fused quartz substrate at different substrate temperatures using a pulsed laser deposition technique. The deposited samples were ex-situ annealed at different temperatures upto 650 °C in air for 2 hrs. It was found that the spontaneous magnetization of the films depends both on the grain size and on the substrat...
Article
Ferrimagnetic Zn-ferrite (ZnFe2O4) films can be grown with the ferromagnetic resonance linewidth of 40 Oe at 9.5 GHz without going through a high temperature processing. This presents interest for applications. The work deals with laser ablated ZnFe2O4 films deposited at O2 pressure of 0.16 mbar onto fused quartz substrates. The films about 120 nm...
Article
We have given a brief account of our research in the field of magnetic multilayers. We have highlighted some our results and contribution.
Article
Full-text available
This work is devoted to the systematic study of the optical and magneto-optical properties of sputter deposited CuFe2O4 thin films in the photon energy region between 2 and 5 eV using spectroscopic ellipsometry and magneto-optical Kerr spectroscopy. The spectral dependence of both the diagonal and off-diagonal elements of the permittivity tensor is...
Article
CoFe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> /ZnFe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www...
Conference Paper
Nanocrystalline Co-ferrite, Zn-ferrite single layers and Co-ferrite/Zn-ferrite bilayer were deposited by the pulsed laser deposition technique on amorphous fused quartz substrate at substrate temperature of 450°C. The magnetic properties of the bilayer and of the single layer films were studied at 300 K and at 10 K. Magnetic measurements at 10 K cl...
Article
Full-text available
The magneto-optical (MO) Kerr effect in CosPt1−s alloys follows from the permittivity tensor component ɛxy times the function v(N) of the refractive index, N. Re(ɛxy) displays a maximum at the photon energy ℏω ≈ 1 eV, |v[N(ℏω)]| increases 30 × from 1 to 6 eV. Re(ɛxy) creates a low ℏω peak in polar Kerr rotation (PKR). The PKR peak above 3.6 eV resu...
Article
This paper is a comprehensive study of different formalisms used to simulate polar magneto-optical (MO) effects in multilayers. A development of the 4 × 4 matrix calculation to first order in off-diagonal elements of the permittivity tensor gives original analytical expressions. They allow to express the MO effects in multilayers as a sum of contri...
Article
High-field magnetization studies performed at 4.2 K in magnetic fields up to 38 T on amorphous Fe80−xHoxB20 alloys have revealed, for samples with the stoichiometry close to that of a compensated ferrimagnet, a magnetic transition. Such a transition is not trivial in systems with a sperimagnetic structure, due to the random local anisotropy, for wh...
Article
Cobalt ferrite thin films of different thicknesses were pulsed-laser deposited onto a fused quartz substrate held at ambient temperature (RT) by varying deposition time. The samples were ex-situ annealed at 750°C in air for 2 hours. All the films were characterized by X-ray diffraction, Raman spectroscopy and energy dispersive X-ray analysis. The s...
Article
The Gd{sub 3}Fe{sub 5}O{sub 12} nanocrystalline Gadolinium Iron Garnet (GdIG) obtained from a sintered block was milled in a high energy ball mill. We measured the magnetization at 5 K under applied fields up to 12 T. We report here our study of approach to saturation magnetization. The results have been interpreted within the framework of random a...
Article
Full-text available
Ferrimagnetic bismuth substituted yttrium iron garnet BixY3−xFe5O12 (BiYIG) films with x=1 and 2 pulsed laser deposited onto (111) Gd3Ga5O12 (GGG) substrates were studied using magneto-optical (MO) Kerr spectroscopy in the photon energy range of 1.8–5eV at both polar and longitudinal magnetizations. The interference at lower photon energies provide...
Article
Nanocrystalline spinel CoFe2O4/ZnFe2O4 bilayers were deposited by the pulsed laser deposition technique on amorphous fused quartz substrate at different substrate temperatures ranging from room temperature to 750 °C. The magnetic properties of the bilayers and of the single layer films deposited in identical conditions were studied at 300 K and at...
Article
Ferromagnetic resonance at 9.5 GHz was performed on ferrimagnetic nano-crystalline Zn-ferrite thin films deposited under different preparation conditions. A very low line width of 40 Oe was observed in as-sputtered 100 W thin films in perpendicular configuration. The pulsed laser deposited films show comparatively higher line widths. This work show...
Article
Full-text available
The magnetic properties of Ni/Pd multilayers, prepared by sequential evaporation in ultrahigh vacuum, have been studied. The Ni thickness dependence of the magnetization and magnetic anisotropy is discussed. The temperature dependence of the spontaneous magnetization is well described by a T3/2 law in all multilayers. A spin-wave theory has been us...
Article
Co-ferrite (CoFe<sub>2</sub>O<sub>4</sub>) thin films were pulsed laser deposited on fused quartz substrate at different substrate temperatures (T<sub>S</sub>) ranging from room temperature (RT) to 750°C in oxygen pressure of 0.16 mbar. All the deposited films were ex-situ annealed at different temperatures (T<sub>A</sub>) between 350 and 1100°C in...
Article
Both single layers (SL) of Tb-Fe and multilayer (ML) TbFe/Al2O3 films have been prepared and the magnetic and magnetooptical properties have been studied as a function of Tb-Fe layer thickness (d,) and modulation characteristics. Perfect rectangular loop is observed only for d1 > 20 na. However in ML, even for d1 -8 nm such characteristics are obta...
Article
Full-text available
Copper ferrite thin films were rf sputtered at a power of 50W. The as deposited films were annealed in air at 800{\deg}C and slow cooled. The transmission electron microscope (TEM) studies were carried out on as deposited as well as on slow cooled film. Significantly larger defect concentration, including stacking faults, was observed in 50W as dep...
Article
Full-text available
The magnetic anisotropy results of Ni/(Au, Ag and Cu) multilayers, prepared by sequential evaporation in ultra high vacuum, were described on the basis of existing models. It is shown that magnetoelastic anisotropy energies Kme of the Ni/(Au, Ag and Cu) multilayers which have fcc (111) perfectly flat interfaces can be expressed with biaxial modulus...
Article
Full-text available
The rf sputtered copper ferrite films contain nanocrystalline grains. In these films, the magnetization does not saturate even in high magnetic fields. This phenomenon of high field susceptibility is attributed to the defects and/or superparamagnetic grains in the films. A simple model is developed to describe the observed high field magnetization...
Article
Full-text available
Copper ferrite thin films were deposited on amorphous quartz substrates. The as deposited films were annealed in air and either quenched or slow cooled. Magnetization studies were carried out on the as deposited as well as annealed films using a SQUID magnetometer. The M-H curves were measured up to a field of 7T, at temperatures varying from 5K to...
Article
Full-text available
The copper ferrite thin films have been deposited by RF sputtering at a 50W rf power. The As-deposited films are annealed in air at $800^{\circ}$C and then slow cooled. The As-deposited (AD) as well as slow cooled (SC) films are studied using a SQUID Magnetometer. The M Vs H curves have been recorded at various temperatures between 5K to 300K. The...
Article
Cobalt ferrite thin films were pulsed laser deposited on fused quartz substrates at different substrate temperatures and ex-situ annealed at 750 degrees C in air. Grain size of these films was found to be 6-44 nm. Magnetization of these nanocrystalline thin films was found to be dependent on the substrate temperature. Magnetization higher than the...
Article
Co-ferrite thin films were prepared by pulsed laser deposition technique at room temperature, and magnetization was studied as a function of annealing temperature (T A ) and annealing time. One set of films was quenched immediately after annealing while the other set was furnace cooled. Spontaneous magnetization value, 4π M S , of the quenched fi...
Article
Co-ferrite thin films were prepared by pulsed laser deposition technique at room temperature, and magnetization was studied as a function of annealing temperature (TA) and annealing time. One set of films was quenched immediately after annealing while the other set was furnace cooled. Spontaneous magnetization value, 4πMS, of the quenched films was...
Article
Temperature dependence of the magnetic properties of magnetite thin film across the Verwey transition has been investigated. As the temperature is decreased, the magnetization of the film in a fixed field showed a sharp decrease close to the Verwey transition temperature (Tv). The M–H loops of the film have been recorded at various temperatures bel...
Article
Amorphous alloys Fe90Zr10 prepared by melt spinning technique have been investigated experimentally and their magnetic properties have been studied. Magnetization measurements have established that the Curie temperature Tc deduced from Arrot plots is about 240 K. The magnetization curves fail to saturate even in field of about 150 kOe. We have dedu...
Conference Paper
Cobalt ferrite thin films were pulsed laser deposited on to fused quartz substrate at a substrate temperature of 350°C. The deposited films were exsitu annealed at different temperatures ranging from 350 to 1100 °C in air for 2 hours. The spontaneous magnetization, 4πMS was found to increase with increase in grain size. Magnetization value of great...
Article
Yttrium iron garnet (YIG) thin films were deposited on fused quartz substrate at different substrate temperatures (Ts) varying from room temperature (RT) to 850°C using pulsed laser deposition (PLD) technique. All the films in the as-deposited state were X-ray amorphous and non-magnetic at RT. The film deposited at RT after annealing at temperature...
Article
Full-text available
Sputter deposited copper ferrite, CuFe2O4, films can be stabilized in two phases at room temperature depending on the deposition conditions and post-deposition heat treatment i.e. in tetragonal phase in slowly cooled (SC) films, or cubic phase in rapidly quenched films. Here we report on the Faraday rotation (FR) and magnetic circular dichroism (MC...
Article
Nanocrystalline magnetite thin film was prepared on to fused quartz substrate by sputtering at an rf power of 50 W. X-ray diffraction study showed that the sputtered film was (110) oriented. The stoichiometry in the thin film has been confirmed through a variety of characterization techniques. The room temperature spontaneous magnetization value (4...
Article
Magnetite thin film with a predominant (1 1 0) texture has been deposited by pulsed laser ablation of alpha-Fe2O3 target onto fused quartz substrate. Spontaneous magnetization of 5400 G and room temperature electrical resistivity of 4.2 x 10(-3) Omega cm were measured for an annealed magnetite thin film. Zero-field-cooled magnetization data clearly...
Article
The magnetization behaviour of amorphous alloys Fe80–xRExB20 (RE = Nd, Sm) with 0 ≤ x ≤ 16, prepared by melt-spinning technique. The effect of rare earth substitution on the magnetic properties (Tc, M0, Hc …) of amorphous alloy has been investigated. Using Random Magnetic Anisotropy Model (RMA), we have analysed our results and obtained some fundam...
Article
Zinc ferrite films were deposited on fused quartz substrate at different temperatures using pulsed laser ablation (PLA) and rf sputtering. X-ray diffraction indicated that all the films were single phase ZnFe2O4 with grain growing in the range of 8–80 nm with substrate temperature. The nanocrystalline films were found to be magnetic and the spontan...
Article
The influence of the addition of a few atomic percents of V on the crystallization temperature, and the magnetic properties of amorphous iron-boron-silicon alloys were investigated using magnetic measurements and Mössbauer spectroscopy. With an increasing V content, the crystallization temperature increases, but the Curie temperature and the magnet...
Article
Rare earth garnets after milling to nanosizes are found to decompose into rare earth orthoferrite and other rare earth and iron oxide phases. The magnetization for the yttrium iron garnet decreases in the nano state due to the formation of antiferromagnetic phases. But for the gadolinium iron garnet when milled up to 25 h, the room temperature magn...
Article
Amorphous Co80−xDyxB20 alloys have been prepared by melt spinning technique and their magnetic properties have been studied. The mean field theory has been used to explain the temperature dependence of the magnetization. High-field magnetization studies performed at 4.2K in magnetic fields up to 38T have revealed, for samples with stoichiometry clo...
Article
Amorphous Fe80−xDyxB20 alloys have been prepared by melt spinning and their magnetic properties have been studied. The mean field theory has been used to explain the temperature dependence of the magnetization. The exchange interactions between Co–Co and Dy–Co atom pairs have been evaluated. High-field magnetization studies on samples with stoichio...
Article
The magnetization of Fe/Pt multilayers has been measured as a function of temperature. For Fe/Pt multilayers with fixed iron layer thickness of 2.5 Å, the magnetization decreases faster with temperature as the platinum layers are made thicker. A simple theoretical model has been used to explain the temperature dependence of the magnetization. From...
Article
The magnetization of Fe/Pt multilayers has been measured as a function of temperature. A bulk-like T3/2 temperature dependence of the magnetization is observed for all multilayers in the temperature range 5–300 K. The spin wave constant B is found to decrease inversely with tFe. A simple theoretical model has been used to explain the temperature de...
Article
The copper ferrite CuFe2O4 films deposited at 50 and 200W RF power on fused quartz substrates and subsequently heat treated were investigated by polar magneto-optic Kerr effect (MOKE) spectroscopy at photon energies ranging from 1.2 to 5eV. CuFe2O4 films can be stabilized in two phases at room temperature depending on deposition conditions and post...
Article
The magnetic properties of sputtered Ni/V multilayers have been studied in a vibrating sample magnetometer, torque magnetometer and by ferromagnetic resonance (FMR). The magnetization decreases with decreasing Ni layer thickness, which is an indication of the structural imperfections at interface. The interface contribution to the magnetic anisotro...
Article
We have grown Ni/Pt multilayers with Pt buffer layer, by evaporation under UHV conditions on glass substrates maintained at 300 K. The magnetic properties of Ni/Pt multilayers are examined as a function of Ni layer thickness tNi. The temperature dependence of the spontaneous magnetization M(T) is well described by a T3/2 law in all multilayers. A s...
Article
The magnetic properties of Ni/V multilayers, prepared by the RF sputtering method, have been systematically studied by magnetic measurements. The magnetization decreases with a decrease in Ni layer thickness tNi and the analysis of the results at 5K indicates the presence of a dead Ni layer about 12Å thick. The effective anisotropy Keff of Ni/V mul...
Article
The magnetic properties of sputtered Fe/Ti multilayers are presented. The magnetization results reveal an interdiffusion at the Fe/Ti interfaces. The FMR spectra were obtained as a function of orientation of the applied magnetic field from in-plane to out-of-plane and were fitted theoretically to determine the magnetic anisotropy. We also observed...
Article
Gadolinium iron garnet was milled in a high energy ball mill to study its magnetic properties in the nanocrystalline regime. XRD reveals the decomposition of the garnet phase into Gd-orthoferrite and Gd2O3 on milling. The variation of saturation magnetization and coercivity with milling is attributed to a possible shift in the compensation temperat...
Article
The magnetic properties of Co/V multilayers, prepared by the e-beam evaporation method, have been systematically studied by magnetic measurements. A bulk-like T3/2 temperature dependence of the magnetization is observed for all multilayers in the temperature range 5–300 K. A simple theoretical model based on an anisotropic ferromagnetic system has...
Article
Full-text available
Thin films of yttrium iron garnet (YIG) were deposited on single crystals of gadolinium gallium garnet (GGG) (111) and Si (100) substrates by pulsed laser deposition (PLD). The films deposited at substrate temperature (Ts) of 750°C on GGG substrates show textured YIG phase. However, films deposited on Si substrates at Ts of 600-750°C, show YFeO3 ph...
Article
The magnetic properties of evaporated Co/V multilayer films have been studied by superconducting quantum interference device magnetometer and ferromagnetic resonance (FMR). The magnetization follows a quasi-linear temperature dependence, which reverts to a T3/2 dependence further into the bulk. We attribute the quasi-linear temperature behavior to...
Article
The magnetization of Co(tCo)/Pt(tPt) (4 tCo10 , 7 tPt20 ) multilayers has been measured as a function of temperature. For Co/Pt multilayers with fixed cobalt layer thickness of 4 , the magnetization decreases faster with temperature as the platinum layers are made thicker. A simple theoretical model based on an anisotropic ferromagnetic system has...
Article
Copper ferrite thin films were prepared using RF sputtering. The films were annealed at various temperatures and subsequently quenched. It was possible to stabilize the cubic phase at room temperature. The magnetization, as a function of annealing temperature, was found to increase monotonically from 1120 G for the as-deposited film to 3550 G for t...
Article
The sputter deposited NiZn ferrite thin films were studied as a function of annealing temperature. The magnetization showed a monotonic increase with increasing annealing temperature. The coercivity shows a minimum at annealing temperature of 400 °C and shows a value of 14 Oe. Transmission electron microscopy study indicated that the grain size inc...
Article
Copper ferrite thin films have been prepared by RF sputtering on quartz substrates. By following successive heating and quenching, it was possible to obtain the films, which showed cubic phase in X-ray diffraction. The grain size was found to be ∼30nm. The magnetization was observed to be of the order of 3000G with a coercivity of 480Oe.
Article
Full-text available
Copper ferrite (CuFe2O4) thin films have been prepared by rf sputtering on fused quartz and silicon (111) substrates at ambient temperature. The as-deposited film is found to be in cubic phase, which is stable only at higher temperatures in bulk. The films were annealed at temperatures ranging from 100 °C to 800 °C and slowly cooled. The films had...
Article
Full-text available
The perpendicular ferromagnetic resonance spectra for four Co/ Nb multilayered films have been studied. Three of these multilayers had the same thickness of Co (210 Å) with Nb layer thicknesses varying between 18 and 135 Å. The fourth film was a trilayer sandwich film. A multimode spectrum was observed for all the films. The results indicated that...
Article
Full-text available
Sputtered Co/Cu multilayers were studied by means of magneto-optical (MO) Kerr spectroscopy. Remarkable changes in the MO spectra were observed for the multilayers where antiferromagnetic coupling take place. This may indicate the changes in the electronic properties of Cu layers. The optical nature of this MO behaviour was verified by ellipsometri...
Article
Summary form only given. Ferromagnetic resonance is a useful tool to study interlayer exchange coupling of multilayers. However, the ferromagnetic resonance (FMR) spectrum becomes complicated when the thickness of the magnetic layer and the number of bilayers are large. We recently developed a model using Hoffmann boundary conditions to explain the...
Article
An amorphous Fe <sub> 67 </sub> Y <sub>33</sub> alloy has been prepared by the melt-spinning method and its magnetic properties have been studied. The thermomagnetization curve is found to obey the Bloch law; spin wave stiffness constant D and the exchange constant A were calculated from the experimental results. From an analysis of the approach to...
Article
We have studied the Mössbauer and magnetization of melt spun amorphous Fe74−xAlxEr6B20 alloys with 0⩽x⩽15. Mössbauer studies were carried at room temperature as well as at 80K. The average hyperfine field values are found to decrease with the Al concentration. Magnetization studies were carried out under magnetic fields up to 140kOe. The results we...
Article
The paper reports on magneto-optic Kerr spectroscopy in a series of [alphaFe2O3/NiO]2.5 multilayers and NiFe2O4 films at the photon energies ranging from 1.2 to 4.5eV. The samples were prepared by pulsed laser deposition onto fused quartz substrates. The thickness of layers and the diffusion of Ni and Fe ions at interfaces were controlled by choice...
Article
Full-text available
Orthoferrites present, as bulk materials, reorientation transitions of their magnetic moment alignment at temperatures depending on the rare-earth (RE) ion. In particular, orthoferrites (REFeO3) with RE = Sm, Dy, present this transition at T SRT = 443 K and 36 K, respectively. The spectra of the complex Kerr and Faraday angle have been measured on...
Article
Measurements and analysis of spectroscopic reflection ellipsometry and magneto-optical polar and longitudinal complex Kerr effect are reported on a natural (111) fece of a high quality NiFe2O4 single-crystal. The experimental reflection data is expressed in terms of the permittivity tensor. This information is employed in modeling experimental pola...
Article
The authors have studied the re-entrant phenomena on the new amorphous Ni80-xFexSi8B12 (2.4<or=x<or=16) alloys. Compositions with x>2.4 show ferromagnetic order. The results indicate the importance of the study of the frequency dependence of chi " in the re-entrant region. A tentative phase diagram is proposed.
Article
EXAFS measurements on the Zn K edge are reported for crystalline and amorphous Mg70Zn30 alloys. The spectra have been found to be identical in the two phases and have been well reconstructed using a multishell modelling. The local structure around the Zn atom is therefore similar in the glassy and crystalline states and shows preferential chemical...
Article
Multilayered Co/Mn films with layer thickness ranging from 10 to 70 AA have been studied by the spin-echo method at liquid helium temperature. The lineshape of the 59Co resonance depends sensitively on the sublayer thickness. The nuclear signal intensity per unit volume in these films was smaller than that arising from a thick single Co layer. For...
Article
Magnetization at 5 K and polar Kerr spectra in CoxNi1-x/Pt multilayers were studied as functions of Co content in order to better understand the difference in the behaviour of interfacial Co and Ni atoms. While the magneto-optic enhancement in the Kerr spectra is observed for the whole range of 0<x<1 the enhancement in the magnetization arising fro...
Article
The magnetization and anisotropy of Fe/Pt multilayers prepared by RF sputtering are presented. The samples with individual Fe thickness of 2.5Å show a dependence of magnetisation on Pt thickness. We found that as the Pt layer became thick enough (>18Å) to magnetically isolate the Fe layers, a quasi-linear temperature dependence of the magnetisation...
Article
Amorphous Fe80−xGdxB20 alloys have been prepared by melt spinning and their magnetic properties have been studied. Mean-field theory has been used to explain the temperature dependence of the magnetization. High-field magnetization studies on samples with stoichiometry close to that of a compensated ferrimagnet show a magnetic behaviour that is cha...