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Mössbauer study of vacuum annealed Fe100-xGax (10 less - than or equal to x less - than or equal to 35) thin films

Szumiata T., Górka B., Brzózka K., Gawroński M., Gzik-Szumiata M., Javed A., Morley N. A., Gibbs M. R. J.

Nukleonika

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2013

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Vol. 58, No. 1

27-30

EN

This work reports results from comparative Mossbauer studies of as-deposited and annealed Fe100.xGax (10 less - than or equal to x less - than or equal to 35) high magnetostrictive thin films of constant thickness (50 plus or minus 2 nm). Films were grown on Si(100) substrates using a co-sputtering and evaporation chamber where Fe has been sputtered and Ga was evaporated. During growth of films, a magnetic field of 65 kA/m has been applied in the plane of the film. Annealed films have been obtained by heating in vacuum for 1 h at 350 centigrade without magnetic field. After annealing, the saturation field of the Fe-Ga films has been significantly reduced. By means of the 57Fe CEMS technique the contributions from several phases have been found: Fe-Ga A2 (bcc), traces of DO3 phase, a gallium-rich disordered phase and iron oxides (both geothite and magnetite). For the sample with x = 26.5 the heat treatment reduces the DO3 phase content whereas for the film with x = 16.4 the opposite tendency has been observed. Mossbauer results were compared with XRD and MOKE findings.

2

Zastosowanie metod jądrowych w badaniach modyfikowanych warstw wierzchnich stali

Sartowska B., Waliś L., Starosta W., Barlak M.

Inżynieria Powierzchni

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2012

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nr 2

74-76

PL

Modyfikację powierzchni stali przeprowadzono przy wykorzystaniu intensywnych impulsów plazmowych (106-108 Wcm-2). Nastąpiło przetopienie warstwy wierzchniej i jednoczesne wprowadzenie wybranych pierwiastków. Materiały wyjściowe i zmodyfikowane zostały scharakteryzowane wykorzystując różne metody badawcze, w tym metody jądrowe takie jak: metoda reakcji jądrowych (NRA), spektroskopia rozpraszania wstecznego Rutherforda (RBS), spektroskopia Mössbauera w wersji elektronów konwersji (CEMS).

EN

Modification processes of steels surface were carried out using intense pulsed plasma beams (106-108 Wcm-2). The surface layers were melted and chosen elements including nitrogen and rare earth elements (REE) were simultaneously incorporated to the melts. Initial and modified materials have been characterized using different investigations methods including nuclear techniques as NRA, RBS and CEMS.

3

The Mössbauer spectroscopy studies of ε to cementite carbides transformation during tempering of high carbon tool steel

Bała P., Krawczyk J., Hanc A.

Archives of Materials Science and Engineering

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2008

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Vol. 32, nr 2

95-98

EN

Purpose: This work presents results of investigations using Mössbauer spectroscopy technique and their interpretation concerning transformation of ε to cementite carbides during tempering in relation to previously conducted dilatometric, microscopic and mechanical investigations. Investigations were performed on 120MnCrMoV8-6-4-2 steel. Design/methodology/approach: Samples taken from investigated steel were austenitized at the temperature of 900°C and hardened in oil. Austenitizing time was 20 minutes. After that, seven of eight samples were tempered. Tempering consisted of holding the samples at 200°C for defined periods. All the times mentioned above were selected basing on IHT (Isothermal Heating Transformations) diagram. Findings: The influence of the tempering time on nucleation and solubility of ε carbides, and on cementite nucleation and growth, was determined. Research limitations/implications: The analysis of phase transformations during various periods of tempering using Mössbauer spectroscopy technique made possible to reveal fine details connected with the processes. Practical implications: Optimum tempering time of tools made from the investigated steel should be in the range of 1.5-2h. Originality/value: Details descriptions of ε to cementite carbides transformation during isothermal heating from as-quenched state.

4

The Mössbauer spectroscopy studies of hypereutectoid cementite precipitation

Krawczyk J., Bała P., Hanc A.

Archives of Materials Science and Engineering

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2008

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Vol. 32, nr 1

45-48

EN

Purpose: of this paper: This work complements the knowledge concerning the hypereutectoid cementite precipitation. Investigations were performed on 120MnCrMoV8-6-4-2 steel, which was designed in 1998, in Phase Transformations Research Group of Department of Physical and Powder Metallurgy at the Faculty of Metals Engineering and Industrial Computer Science at AGH University of Science and Technology in Kraków. Design/methodology/approach: Samples of investigated steel were austenitized at the temperature of 900°C and hardened in oil. Next, four from five samples were tempered. Tempering consisted of heating the samples up to chosen temperatures with a heating rate of 0.05°C/s and, after reaching desired temperature, fast cooling. CEMS technique was applied for Mössbauer studies. Findings: Secondary cementite remaining in the microstructure of 120MnCrMoV8-6-4-2 steel hardened from 900°C is alloyed to a degree which allows paramagnetism. Research limitations/implications: The influence of hypereutectoid cementite on the cementite precipitations during continuous heating from as-quenched state of high carbon Cr-Mn-Mo steel was determined. Practical implications: The knowledge of the influence of hypereutectoid cementite on the cementite precipitations during continuous heating enables proper design of the heat treatment of 120MnCrMoV8-6-4-2 steel in respect to its application for hot working tools. Originality/value: Measurements of the isomeric shift for secondary cementite allowed to determine changes in level of stresses occurring in hardened steel.

5

The influence of Co and V substitution on structural properties of FINEMET-type alloys

Szumiata T., Gawroński M., Brzózka K., Górka B., Sovák P., Pavlík P.

Nukleonika

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2007

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Vol. 52, supl. 1

21-28

EN

The effect of addition of Co and V on the hyperfine parameters of amorphous as well as nanocrystalline Finemet-type alloys has been studied by means of transmission Mössbauer spectrometry. It was stated that these elements infiltrate into crystalline grains in the course of crystallization, what causes alteration in structure. Different evolution of magnetic hyperfine field is reported in both cases and analyzed. In the series of alloys substituted by vanadium, the substantial paramagnetic component attributed to iron-poor regions in the amorphous remainder was found.

6

Simultaneous transmission and scattering Mössbauer measurements of powder samples

Fornal P., Stanek J.

Nukleonika

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2007

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Vol. 52, supl. 1

13-16

EN

A vertical experimental set-up for simultaneous recording transmission and scattering Mössbauer spectra is described. Application of the apparatus for the study of model powder mixture of two components with different grain sizes shows differences in the relative intensity ratio of these fractions in absorption and conversion electron Mössbauer spectroscopy (CEMS) spectra. This effect, explained as a result of the size selectivity of CEMS technique, is parameterized by the grain radius ratio of components. The possible application for investigation of isolated surface nano- and microobjects is discussed.

7

Magnetic texture determination by CEMS with polarized radiation

Olszewski K., Szymański K., Satuła D., Dobrzyński L.

Nukleonika

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2007

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Vol. 52, supl. 1

17-19

EN

CEMS measurements of a 57Fe foil were performed with unpolarized and polarized radiation. It is shown that the experimental results permit determination of important characteristics of a magnetic texture, an average square of the cosine((gamma-m)2) and an average cosine (gamma-m).

8

Uniaxal magnetic properties of sputtered FeB/Cu/FeB trilayers deposited onto bowed substrates

Stobiecki T., Wrona J., Czapkiewicz M., Prados C., Castano F. J., Garcia D., Vazquez M., Kopcewicz M., Grabias A., Żuberek R

Elektronika : konstrukcje, technologie, zastosowania

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2000

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Vol. 41, nr 11

45-47

EN

Fe20/Cu/Fe_{80B_{20 trilayers were deposited onto bowed glass substrates using the RF sputtering technique. On removing the trilayerssystem from the sputtering chamber, a magnetoelestic uniaxial in-plane anisotropy was induced due to the compressive stress developed when the substrates recovered their initial shape. For the one type of the sample the permanent stress was applied in both FeB bottom and top layer in the same directions (parallel to the longer axis of the glass slide). For the second type of the sample the stress was applied for the bottom FeB layer under +21° and top layer under - 21° angle (with respect to the longer axis of the glass slide). It was found, using Kerr magnetometry, that due to the positive magnetostriction nature of the FeB layers the directions of the easy axis have been induced separately in each FeB sublayer. The magnetic and magnetoelastic properties of these samples are discussed.}}

PL

Oddziaływania magnetosprężyste umożliwiają indukowanie magnetycznej anizotropii jednoosiowej przez zastosowanie zewnętrznych naprężeń w układach wielowarstwowych. Na przykładzie trójwarstwowego układu Fe80B20(500 Å)/ Cu(40A)/Fe80B20(500 Å) złożonego z amorficznych warstw stopu FeB i polikrystalicznej przekładki Cu badano magnetyczne oddziaływanie międzywarstwowe i efekt anizotropii jednoosiowej. Warstwy nanoszono metodą zmienno-prądowego (RF) rozpylenia jonowego na wygięte podłoża szklane o wymiarach (50x22x0.15 mm). Warstwy zabezpieczono przed utlenianiem nanosząc na końcu 20 Å warstwę Cu. Wygięcie podłoża było precyzyjnie regulowane i zapewniało dodatnie naprężenie 3.5x10-4 powierzchni szkła, na którą nanoszono układ trójwarstwowy. Po zakończeniu nanosze nia układ wielowarstwowy powracał do pozycji płaskiej. Dwa typy próbek poddano badaniom. Dla pierwszego rodzaju (ang.0) naprężenie ściskające było przyłożone w kierunku dłuższej krawędzi podłoża podczas nanoszenia zarówno górnej, jak i dolnej warstwy FeB. Natomiast dla drugiego ro dzaju próbek (ang.21) naprężenie ściskające przyłożono pod kątem +21° podczas nanoszenia dolnej warstwy FeB i -21° podczas nanoszenia warstwy górnej (kąt liczony względem dłuższej krawędzi podłoża). Próbki scharakteryzowano strukturalnie stwierdzając stan amorficzny warstw Fe80B20 za pomocą dyfrakcji rentgenowskiej i spektroskopii mossbauerowskiej elektronów konwersji (CEMS). Wykaza no, za pomocą pomiarów pętli histerezy, otrzymanych z magnetooptycznego efektu Kerra (MOKE), że poprzez dodat nią magnetostrykcję Fe80B20, w wyniku oddziaływania magnetoelastycznego podczas procesu nanoszenia w każdej warstwie niezależnie od kierunku przyłożonych naprężeń indukuje się jednoosiowa anizotropia magnetyczna. Pomiary magnetostrykcji, magnetorezystancji i namagnesowania potwierdzają silną anizotropię jednoosiową w badanych układach trójwarstwowych.